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sci.electronics
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re building a uv flashlight you can get a little uv by putting a heavy uv filter deep purple in front of an ordinary flashlight bulb the brightest you can get my father used a setup like this in law enforcement work circa good uv blacklight bulbs work like fluorescent bulbs i d proceed by getting a cheap battery powered fluorescent light then going to an electrical supply house and finding a uv bulb that would fit it michael a covington associate research scientist artificial intelligence programs mcovingt ai uga edu the university of georgia phone athens georgia u s a amateur radio n tmi
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re telephone controlled power bar needed i had a similar idea for a fax answering machine switch to put both machines on one line you order distinctive ringing from your phone company this is month here you get a second unpublished phone number when someone calls this number your phone rings with short rings instead of long rings you set up your answering machine on rings and your fax on six rings you d give out the new as your fax a device would measure the length of rings when it detects a short ring it turns off your answering machine five rings later your fax picks up the call this should be cheaper and more elegant than the switches now available but that s not what i did i m giving out the new to my friends and customers this should leave the old for telemarketers etc i won t pick up the phone when i hear the long rings why my thoughts are my own when they are in but when they are out they are another s susannah martin hanged for witchcraft thomas david kehoe kehoe netcom com
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atari processors does anyone know what processor the atari used what i m looking for is th e pin outs for the atari the schematics for it it does anyone have any idea where i could find this or any related information this is very impor tant also are the rom chips that were used fo rthe games still available or were they propreitary please email me with any responces as this is very important thanks a million btw anyone who works has worked for atari i could really use your help with i nfo on the old please email me if you are willing to help me thatnks alot peter
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re dmm advice needed i ve had my fluke a here at work for just over years now it is a wonderful meter several colleagues here have some of the newer fluke meters though i still would just as soon hang on to my the a is the s digial analog to the simpson analog dmm of the s there was is an b that had extended frequency response i ve got a nifty little pen shaped meter made by soar that i keep in my toolbox at home i ve had that for six or seven years now and only replaced the batteries a couple of timees it is more than adequate for day to day hobby use i think soar oems their stuff for a number of vendors some of jdr microdevices stuff looks rather similar to soar s bill mayhew neoucom computer services department rootstown oh usa phone wtm uhura neoucom edu n wed
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re help how to reduce the rpms of a boxer fan yes you increase the rpm slip of a boxer type fan by installing a capacitor in series with the fan s power supply the air flow of small inch fans can be reduced by about by using a to uf capacitor use a good grade nonpolarized unit with working voltage rating around volts note that some impriical study is usually required to experimentally determine the best size capacitor for a given application for dc powered applications try the radio shack volt box fan it can run and start reliably from as low as about vdc it is exceptionally quiet but at admittedly low flow i wish i knew who made the fans for radio shack bill mayhew neoucom computer services department rootstown oh usa phone wtm uhura neoucom edu n wed
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eeg kit awhile back someone posted some information on where you can get kits to build an eeg does anyone remember where you could get this i m very interested in getting some info on this thanks in advance eric cantrell sauron msfc nasa
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re radar detector detectors it is illegal to use anything you eavedropped on for a business or for an illegal use jurisdictions that ban radar detectors or police monitors are essentially making the claim that there is no other reason for a radar detector or police radio monitor the results of fighting these claims in courts have been mixed the federal courts are not anxious to intervene and state courts have sometimes held that the feds have exclusive jurisdiction and sometimes they have not a lot of state courts do not have enough imagination to see any use for a radar detector besides avoiding law enforcement action for speeding when you buy a radar detector amongst the guarrantees instructions explanations and other detritus is an invitation to join an association dedicated to preserving your right to use a radar detector i promise i am not making this up i do not think radar detector manufacturers would be making any headway at all in courtrooms if police departments enforced speed laws with a strict eye to public safety and a blind eye to the fund raiser aspect of tickets mike coyne
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re dayton hamfest yes take interstate i to the route exit go south on about miles trun right on shiloh springs road the hamvention is at the harrah arena which is about mile west and on the north side of the road parking at the arena is limited lodging is probably entirely booked up within a mile radius good luck i i x mall s springs it is possible to park at the mall to the west there are shuttle busses running between the arena and the mall if possible get a montgomery county oh map from your local aaa office it should be free if you are an aaa member if you don t already have definite plans now is not a particularly good time to start to think about going to the hamvention bill mayhew neoucom computer services department rootstown oh usa phone wtm uhura neoucom edu n wed
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need help with video detection circuit i am trying to build a circuit that detects the presence of video vs a blank screen by monitoring the r g and b outputs of a graphics card it should be able to detect the presence of a single pixel at mhz which would mean detecting a ns pulse it should also be able to tell the difference between a blank screen about mv and a dim screen say around mv oh yes it also needs to be cheap my first circuit was a dismal failure i used compariators each compariator had the input going to one of the guns the input went to a reference created by a voltage divider a potentiometer the first problem was that the compariator was way too slow i needed to get several pixels in a row before it would fire the compariators so i could have a whole screen full of text but my circuit would not detect it the second problem is that there was more noise on the reference then the smallest difference between a blank screen and a dim screen in fact the difference between completely black and completely white is only mv i am wondering if i am going to have to amplify the video signals to make this work there are faster compariators but they are expensive and require split supplies i would need to replace my quad compariator with three compariators and create a whole new power supply circuit at this point i think what i need is some sort of transistor circuit transistors are fast and cheap and should do the trick unfortunately i am way out of my league when it comes to designing transistor circuits so i am appealing to the net for help any ideas tips circuits pointers references etc would be greatly appreciated oh yes i only sample the output of this thing every second or so so i don t need a fast response time at all however i haven t found a way to take advantage of that fact thanks a lot for any help anybody might be able to give of course you will have my undying gratitude steve verity steve verity maxed on midi verity jack sns com
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long distance ir detection i would like to be able to detect the angular position low accuracy of an ir emitting source at a distance of about meters more is better in daylight the ir source could be emitting a signature i m leaning toward khz square wave with duty cycle i am considering the use of a quadrant detector from centronic inc to give information to a pan tilt head to point the sensor and thus determine the angles for the source i am considering wazing the heck out of an ir led s possibly an optek op or motorola mled wazing would mean at least amp current pulses at this current the duty cycle of the led drops to and i would need to cycle five of them in turn to get the required has anyone done something like this stan burton dnd crad dres dtd mss agcg sburton dres dnd ca dre suffield box medicine hat ab canada t a k
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re power signal surges in home in article randall woof randall informix com randall rhea writes gstovall crchh nosubdomain nodomain greg stovall writes anyway over the weekend i was resting on the sofa in between chores and noticed that i briefly picked up what sounded like ham radio traffic over my stereo and television even though both were off also all the touch sensitive lights in my house start going wacko cycling through their four brightness states i presume that some ham operator with an illegal amplifier drove past my house i live on a busy thoroughfare would this be a correct presumption what kind of power must he be putting out to cause the effects the affected equipment is about feet from the road hams are unlikely to have an illegal amp and are also unlikely to have a dirty amp hams can legally run up to watts it is very unlikely however that a ham would be running that kind of power from a car ham rigs not possible either you d need about a amp alternator for just the amplifier i can just see it you need to slow down on a downgrade so you hit the push to talk button for cars put out around watts it is possible that a watt radio would cause interference to consumer electronic feet away most tvs stereos and vcrs have very poor rf shielding if you experience the problem frequently it may be caused by a ham cber or other radio operator in a base station nearby the interference may have been caused by a radio transmitter used for other purposes such as police fire etc if you heard voices over your stereo i think you are correct in assuming that the source is an rf transmitter if you have frequent trouble you may want to try the rf ferrite chokes available at radio shack the interference is probably being picked up by your speaker wires and those chokes can be installed on the wires very easily without cutting them good instructions are included with the chokes if that does not solve the problem you may want to search your neighborhood for a radio operator look for antennas on the roof or car talk to him her about your problem there are things a radio operator can do to reduce interference and please remember to be friendly when approaching your local radio operator this person may or may not be the cause of your troubles and you ll get better cooperation and help if you assume that he is going to be helpful most are it was amazing the accusations that we sometimes dealt with as i grew up we were blamed for skip ghost pictures on the tv that occur at sunspot peaks c b interferance dead grass you name it btw the local operator should try and help you whether or not he or she is directly responsible it is part of being a good neighbor and that is how the fcc views it too bad they don t require the consumer equipment makers to take any precautions last you can usually tell ham radio vs cb ham operators are required to declare their call sign every so many minutes no more than so if you hear this is wa qt or some other call starting with a w or k and no more than total characters you heard a ham cb ers probably won t sign i don t know that they re even required to and fire police have other private ids douglas s rand drand osf org osf motif dev snail cambridge center cambridge ma disclaimer i don t know if osf agrees with me let s vote on it amateur radio kc kj
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laser vs bubblejet well i m not too sure if this would be the right place to post this but anyway here goes i was just noticing that some of the current bubblejet printers offers up to x resolution while a lot of lower end laser printers only offer x however the laser printers still seems to be significantly pricier than the bubblejets how is this or am i missing something about the resolution thing sheng hl pl eecs lehigh edu hl m k cc lehigh edu hl lehigh edu
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re mc sbi mixer musone acsu buffalo edu mark j musone writes p s any really good books on am fm theory along with detailed electrical diagrams would help a lot i have seen a lot of theory books with no circuits and a lot of circuit books with no theory but one without the other does not help mixers have a wide variety of implementations the mini circuits part you mention is a doubly balanced diode mixer but active ones bjt fet seem more popular in consumer receivers you might call mcl they have a nice catalog the universal answer for wide coverage theory practice rf design is the arrl handbook published by the american radio relay league the radio amateur organization any technical bookstore can order you one the book is superb with lots of accessible theory construction projects and generally interesting stuff you might also check out solid state design for the radio amateur i think by hayward and someone this has sharper design and test information about subsystems like mixers peter monta monta image mit edu mit advanced television research program
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how do i make me own really short run cd s i want to be able to take a bunch of home made songs from dat or other suitable master and output them to a short run off of standard music cds would one of the cd recorders designed for writeable cd roms work for this purpose alternatively is there a service that does this sort of thing for a fee i m after as much information as possible on the alternatives cost lead time equipment required procedure to follow etc email replies would be appreciated geva patz geva department of computer science wits university geva concave cs wits ac za
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how to the disks copy protected i was wondering what copy protection techniques are avaliable and how effective are they has anyone have any experience in this area with highest regards babak sehari
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w c w c info wanted does anybody have informations about the w c and w c chips pin dil pckg they are build in a multifunction io card for pc thanks dirk dirk junghanns junghanns rz tu ilmenau de
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re power signal surges in home drand spinner osf org douglas s rand writes hams can legally run up to watts it is very unlikely however that a ham would be running that kind of power from a car not possible either you d need about a amp alternator for just the amplifier it is too possible as the original poster said it is very unlikely but definately possible can you say batteries
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pads question how do i go from a schematic pcb after i have produced a schematic with pads logic how do i import it into pads pcb to create a pcb pattern the only way i ve gotten it to work is to output a futurenet netlist and then import this into pads pcb is there another way of doing this i didn t see any information in the instructions provided but i might have missed something any suggestions would be greatly appreciated thanks i i raymond yeung internet nimbus uiuc edu rky uxa cso uiuc edu ee student at the university of illinois compuserve at urbana champaign i i
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need help on i need help on components bat diode i know digi key or newark sells them but the minimum order is does anyone know where i can get smaller orders of this diode or an equivalent replacement bc b transistor ditto for this transistor hc chip digi key newark and mouser do not appear to carry ths chip does anyone know what this does and where i can obtain it ym b chip this yamaha chip decodes s pdif data from cd or dat where can i obtain one of these thanks in advance ian
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re laser vs bubblejet in article apr ns cc lehigh edu hl ns cc lehigh edu hou sheng lin writes well i m not too sure if this would be the right place to post this but anyway here goes i was just noticing that some of the current bubblejet printers offers up to x resolution while a lot of lower end laser printers only offer x however the laser printers still seems to be significantly pricier than the bubblejets how is this or am i missing something about the resolution thing bubblejets often splatter a little bit whereas laserjets given half way decent toner like hp s microfine stuff don t both produce very good output but you don t have to look too closely at the two to tell that laserjet output is definitely superior on the other hand laserjets which haven t been maintained properly and use the cheapest toner the owner could find often produce awful output much worse than a bubblejet one other thing there are bubblejets and then there are bubblejets there are a few bubblejets out there that produce rather mediocre output such as hp s dinky little bubblejet whereas most produce really good looking output such as hp s deskjets ibm and canon both produce some of the really good style bubblejets joel kolstad p s if you re in the market for a portable bublejet printer i can highly recommend the hp portable deskjet although i ve heard the portable canons are good too i needed pcl support myself with the deskjet portable you even get an undocumented pcmcia card slot
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decoupling caps onboard posted for a friend hello there i would like to know if any one had any experience with having on board decoupling capacitors inside a cmos chip for the power lines say i have a lot of space left im my pad limited design any data on the effect of oxide breakdown any info or pointers are appreciated rs
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re eeg kit in article cantrell sauron msfc nasa gov cantrell sauron msfc nasa gov eric cantrell writes awhile back someone posted some information on where you can get kits to build an eeg does anyone remember where you could get this i m very interested in getting some info on this thanks in advance eric cantrell sauron msfc nasa contact circuit cellar inc park st suite vernon ct fax and inquire about hal eeg biofeedback brainwave analyzer in addition if you want to build your own system from board level compo nents biosignal amplifiers analog isolators and isolated multiplexers you can contact the davron group p o box deerfield il fax david david prutchi hc dt washington university prutchi mesun wustl edu campus box dp cec wustl edu one brookings drive st louis mo
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re long distance ir detection in article apr dres dnd ca sburton dres dnd ca stan burton writes i would like to be able to detect the angular position low accuracy of an ir emitting source at a distance of about meters more is better in daylight the ir source could be emitting a signature i m leaning toward khz square wave with duty cycle i am considering the use of a quadrant detector from centronic inc to give information to a pan tilt head to point the sensor and thus determine the angles for the source i am considering wazing the heck out of an ir led s possibly an optek op or motorola mled wazing would mean at least amp current pulses at this current the duty cycle of the led drops to and i would need to cycle five of them in turn to get the required has anyone done something like this stan burton dnd crad dres dtd mss agcg sburton dres dnd ca dre suffield box medicine hat ab canada t a k a method which will directly almost provide you with the information that you require is that which is commonly used for coordinate measurements of human body landmarks eg the selspot system by selspot ab sweden and the watsmart system these use lateral photoeffect detectors lindholm and oberg woltring and marsolais to determine the position of a spot of light projected using a camera lens over its surface in escence the detector is a large photodiode with four cathodes one on each of the four sides of the square detector crystal and a single anode the back of the crystal a spot of light will produce currents which are proportional to the position of the spot on the detector s face let s try some ascii graphics in d so the detector has two cathodes to detect linear position cathode xxxxx xxxxx light xxxxx divider output xxxxx xxxxx xxxxx xxxxx gnd xxxxx xxxxx anode xxxxx cathode if the dot of light from the led is the only source of light then the position of the projection is given by this circuit regardless of the level of illumina tion the divider is used to normalize relative to total received power when this circuit is used in the presence of other sources of light then the way of tuning to it is to sample for a few msec the background signal light the led for an equal time and sample that signal separately the difference between the two is the position of the led hamamatsu photonics sells linear and d lateral photoeffect detectors and they also sell the required signal processing electronics the ready made systems by selspot and others are not cheap lindholm l e and k e oberg an optoelectronic instrument for remote on line movement monitoring biotelemetry woltring h j and e b marsolais opto electronic selspot gait measure ments in two and three dimensional space a preliminary report bull pros thetics research most probably this technique can provide you with a much more accurate measurement than you need but i think that its simplicity beats scanning a quadrant detector with a pan tilt system until you reach zero difference david david prutchi hc dt washington university prutchi mesun wustl edu campus box dp cec wustl edu one brookings drive st louis mo
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infra red position encoders i am looking for information on infra red based position encoders the idea would be to bounce the infrared source off a wall and the device would read out the distance preferable it would be rs addressable any leads chris kushmerick kushmer bnlux bnl gov i found my niche in life i just didn t fit in
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re swr meter for cb radios in article aa insane apana org au peter m insane apana org au peter tryndoch writes allthe devil reincarnateswr meter for cb radios td from ssave ole cdac com the devil reincarnate td organization cdac wa td what td is a good choice for a cb or wave td i read the installation instructions on a wave antenna td and they suggested that i use an swr to tune it at channel td and channel for a minimum reading question is why channel td and the best antenna is one that will let out the most wave probably not the best explanation but the rest makes sense a one wave will cancell itself out btw no such beastie yes there is not common for cb the pattern is different sort of a cloverleaf with four main lobes the best is a wave antenna followed by then etc use of anything under wave for transmitting is very uncommon the usual rubber duck uses a coil to fool itself into looking like a quarter wave i reccomend the arrl antenna handbook or a good basic book thanks dave pierson the facts as accurately as i can manage digital equipment corporation the opinions my own old bolton rd i am the nra stow mass usa pierson msd enet dec com he has read everything and to his credit written nothing a j raffles
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need info on dsp project i want to start a dsp project that can maniplate music in a stereo cassette is that any chip set development kit and or compiler that can equilize mix music ideally the system should have d a a d converters a dsp compiler a rough estimate of the cost is greately appreciated thanks in advance regards jing chin e mail address chin bode ee ualberta ca
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re pinout needed for til according to my ti databook the pinouts for the til display are as follows pin led supply voltage pin latch data input b pin latch data input a pin left decimal point cathode pin latch strobe input pin omitted pin common ground pin blanking input pin omitted pin right decimal point cathode pin omitted pin latch data input d pin latch data input c pin logic supply voltage vcc the logic supply voltage is v ma the led supply is also v but it need not be particularly well regulated the led drivers on the chip use a constant current source so led intensity is not affected by the supply voltage o o kelly gray gray feline uucp preferred gray admin humberc on ca
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re how to the disks copy protected in article sehari marge ecss iastate edu sehari iastate edu babak sehari writes i was wondering what copy protection techniques are avaliable and how effective are they has anyone have any experience in this area with highest regards babak sehari uh oh umm there are a number of copy protection schemes some involve modifying the physical media and some involve encryption schemes c all of the ones that have existed over the course of computing have been successful for a time i recall however near monthly releases of new ways to crack the copy protection scheme of the latest releases the fact is none of them are completely secure or anywhere near it some are more or less difficult to crack and some have already been cracked i guess what i am saying is that your question is difficult if not impossible to answer what exactly do you want to know do you need a good one for a project you are working on how secure must it be are you trying to crack one that someone else has used i can probably make suggestions assuming the activity is strictly legal in general it is a bad idea legally to tamper with copy protection it can also lead to corruption of files which you necessarily do not have back ups of being as they are copy protected which can be devestating do you have absolutely no ideas for practical applications and are merely curious please clear up those questions and i ll try to help as much as i can incidentally the uh oh at the top is indicative of the dread anyone who has watched their friends hacking equipment be carted off feels when they are asked how to hack the area you are broaching is wrought with dangers many of which include breaking the law or at least addressing it from one side or the other matt
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re building a uv flashlight jhawk panix com john hawkinson writes my main question is the bulb where can i get uv bulbs do they need a lot of power etc etc he ones i have seen are all fluorescent tubes maybe you could find a small tube to go in one of those hand held fluoro lanterns one other thing a friend of mine mentioned something about near uv light being cheaper to get at than actual uv light does anyone know what he was referring to blue lights ultra violet by definition goes from the blue end of the spectrum that people see to the radio spectrum x rays cosmic rays etc possibly you could get light at the fringe of visibility which people with false eye lenses can see easily since it s your lenses that soak up most of the uv however since most people use uv to get other things to glow and the near blue is less energetic it would probably not work as well if it worked at all lecture on basic atomic physics fits in here about electron transitions quantum leaps and stuff moz
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re power signal surges in home in article drand apr spinner osf org drand spinner osf org douglas s rand writes in article randall woof randall informix com randall rhea writes hams can legally run up to watts it is very unlikely however that a ham would be running that kind of power from a car ham rigs not possible either you d need about a amp alternator for just the amplifier i can just see it you need to slow down on a downgrade so you hit the push to talk button now that indeed is possible a good friend of mine is running about kw pep from his car yes he does have a second alternator yes he calls the rig an electronic brake since the engine noticeably slows when the key is down my car unfortunately has so much computer junk under the hood that it s astonishingly sensitive to rfi if i key a w ht over the engine with the hood open the car loses timing due to the rf leaking into the distributor pickup very poor design i will however point out that ham radio operators are usually quite willing to help when interference is detected remember that any interference is wasted power if i put out w in the tv band that s w that i am not putting out in the band i am trying to transmit on and w can often be the difference between a nice card hanging on the wall and nothing cbers however are usually not as helpful most illegal cbers however will stop operation when you inform them of a problem the rest of them will stop operation when you inform the local fcc office of the problem in writing and giving details and addresses last you can usually tell ham radio vs cb ham operators are required to declare their call sign every so many minutes no more than so if you hear this is wa qt or some other call starting with a w or k and no more than total characters you heard a ham cb ers probably won t sign i don t know that they re even required to and fire police have other private ids good advice hams will frequently give their call and will never use a handle they are less apt to use immense amounts of profanity as well but that s not to say that they don t from time to time scott
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digital voltmeter how does it work hello let me introduce a problem when i measure a sinusoidal wave voltage with a digital voltmeter using ac mode my output is an rms value a peak value over squared right when i measure a square wave in the same mode ac my output is equal to a peak value actually to the upper flat boundary of the wave i assumed that a digital voltmeter makes some kind of integration of the input value and divides it over the wave period right now i used it to measure the same square wave as above but distorted by high frequency harmonics ideally output should be the same but the output value was only about of the previous one why what is the nature of this output value what does the voltmeter actually measure and what does it show related question less important to me what are advantages and disadvantages of digital voltmeters to compare with analog ones thank you for your attention you could mail me your opinion at avm zeus tamu edu or open a discussion here i would appreciate either way alexander v mamishev power system automation laboratory phone office department of electrical engineering phone home texas a m university fax college station tx usa internet avm zeus tamu edu
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re need to find out number to a phone line in article mindlink bc ca sean oliver mindlink bc ca sean oliver writes joseph mich krzeszewsk writes the phone company will read the number of the phone you are on where i live i use bctel the number to dial is for the same result in ny city the number to dial is it seems to be different in different areas anders
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re how to the disks copy protected in article sehari marge ecss iastate edu sehari iastate edu babak sehari writes i was wondering what copy protection techniques are avaliable and how effective are they has anyone have any experience in this area with highest regards babak sehari one of the easiest and really very used ways of copyprotection is to mark a specific sector on the installation disk bad this is very easy to get around though if you have any knowledge of hw hacking but most normal users yes those lowly key punchers don t whatever you do please do not use a hardware key these were very popular a few years ago and they stink mail mail gunnarh sofus dhhalden no snail mail gunnar horrigmo gunnarh fenris dhhalden no oskleiva n norway disclaimer the above posting may seem like insignificant rubbish at first glance but if you read between the lines you will be surprised to discover the annals of burt bacharach world peace oxford advanced readers dictionary quantum physics made easy and an easy to use step by step walkthrough on how to make a time travelling device that actually works
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re building a uv flashlight in article c r lz n panix com jhawk panix com john hawkinson writes one other thing a friend of mine mentioned something about near uv light being cheaper to get at than actual uv light does anyone know what he was referring to i don t want to get into a semantic argument but contrary to some other postings near uv light is actual uv light the near means that it is close to the visible spectrum i e of relatively long wavelength not that it is nearly uv i m sure you can figure out now just what far uv is regular incandenscent flashlight bulbs emit tiny amounts of uv in the near end of the spectrum such that a filter can be used to remove the visible light and thus create a weak uv source stronger sources are going to require gas probably mercury vapor discharge tubes such as fluorescent tubes with uv phosphor be careful though strong uv sources can cause physiological damage especially to the eyes the shorter wavelengths are the most dangerous it wouldn t project a beam like a flashlight but replacing the tubes in a portable fluorescent lantern with uv tubes would be a relatively cheap way to create a portable source it would be bright enough to be useful but not dangerously so ed hall edhall rand org
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re power signal surges in home kludge grissom larc nasa gov scott dorsey writes my car unfortunately has so much computer junk under the hood that it s astonishingly sensitive to rfi if i key a w ht over the engine with the hood open the car loses timing due to the rf leaking into the distributor pickup very poor design there was a news article a little while ago reporting a type of car was it a volvo was found to stall if you used a certain brand model of cellular phone in it i seem to remember the car was recalled to fix the problem hmmmmm this has possibilities if the police are in pursuit of a vehicle maybe they can bombard it with high energy rfi
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re help wanted in article apr csc canberra edu au u student canberra edu au ogawa taro stephen ise writes could someone please tell me if a decoder is the same as a to demultiplexer i know how to link of these to get an output circuit but how do i link of these to make a multiplexer sorry if this seems like a lame question but i m only a newbie to electronics and i have to do this circuit please make any mail as droolproof as possible thanx taro ogawa u student canberra edu au a of decoder need not be the same as a to demultiplexer although many commercial ssi implementations allow you to use one as such strictly a of decoder need only take two lines in and make one output change state according to the inputs a demux on the other hand uses two control inputs to determine which of four outputs will reflect the state of the input signal so there are three inputs required a decoder can be used as a demux if it is equipped with an output enable input since this can be used as the data input e g when high all outputs are high when low only the selected by control inputs output will be low an eight way decoder is created by using the high order bit bit to select which of two four way demuxes is enabled thus you achieve your aim of having only one output of eight reflecting the input bits note that this method cannot be used to create a true eight way demux since you have no data input the enable line on a four way decoder left once you commit the enable lines to their intended purpose a sixteen way decoder obviously requires four four way decoders plus a mechanism to enable only one of the four at a time therefore use the fifth decoder attached to the two high order bits to provide the four enable lines of course the two low order bits must be connected in parallel to the four final stage decoders please give me the credit when you submit your homework johnh electronics department school of mpce macquarie university sydney australia email johnh mpce mq edu au ph fax
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mosfet help since i m not all too keen on this area of hooking them up i m asking for help i know better than to hook a v a stepper line to one unless it can take it however what about if i ve got a v stepper what sort of curent limmiting circuitry would be involved a small schematic would probably be helpfull also i ve looked into the tipc n by ti and i was wondering if i should use the same suggested by you replying to this message current limiting circuitry on each of the mosfets in the package as that illustrated in the schematic which you the replyer would hopefully help me with hmm different request thanks inspiration comes to o baden sys bison mb ca those who baden inqmind bison mb ca seek the baden de bari unknown baden inqmind bison mb ca the inquiring mind bbs winnipeg manitoba
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re minimal boolean circuit in article apr ringer cs utsa edu djimenez ringer cs utsa edu daniel jimenez writes suppose we have a boolean function which is a minimal sum of products derived from a k map or something like this f a b c d bc d acd abc ab c the books on logic design i have consulted all seem to imply that this is where the analysis ends but by factoring out the a term in the function we can get fewer gates f a b c d bc d a cd bc b c which yields gates yes but the minimization of gates is important in part because of timing considerations a ttl gate has the basic structure of and or invert and an inversion of a sum of a product is just exactly one gate delay the reason to find a minimal sum of products is that this matches a hardware optimization a positive or gate such as the gate solution uses has two gate delays and there s another gate delay in the second term so that the second solution while simpler in logic symbols can be expected to be something less than optimal in the real world ecl is similar to ttl in that it can support an or and gate with the minimum delay unlike ttl you get both true and inverse outputs for free when using ecl pals are basically large programmable and or invert gates with your choice of internal connections between the various sections and perhaps some latches so a minimum sum of products also is a way to shoehorn a logic design into a few pals it s not comparably easy to design with a minimization of logic gates but some software packages claim to allow you to do so and will take just about any mess of gates as a nodelist with xxx series logic ics and produce a description of a logic cell array to do the same job xilinx s xact software does this by treating each logic block as a macro and expanding it all out then simplifying john whitmore
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integrated cct type um c l manufac by umc where can i buy or of these chips pref in australia what is name and address of umc dan adrian blockley i may say something profound environmental science here one day murdoch university western australia blockley essun murdoch edu au phone
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re digital voltmeter how does it work mamishev alexander valentino avm sigma tamu edu wrote hello let me introduce a problem when i measure a sinusoidal wave voltage with a digital voltmeter using ac mode my output is an rms value a peak value over squared right when i measure a square wave in the same mode ac my output is equal to a peak value actually to the upper flat boundary of the wave i assumed that a digital voltmeter makes some kind of integration of the input value and divides it over the wave period right now i used it to measure the same square wave as above but distorted by high frequency harmonics ideally output should be the same but the output value was only about of the previous one why what is the nature of this output value what does the voltmeter actually measure and what does it show re rms readings unless the dvm says it s measuring rms it s probably average voltage the input is diode rectified and measured as dc if it says it s rms and but measures square triangle etc incorrectly it s measuring average and multipling by a correction that s only true for sine waves i e vave vrms if you want correct rms for most any waveform you need a true rms dvm dmm which literally does the root mean square calculation in either analog or digital circuitry related question less important to me what are advantages and disadvantages of digital voltmeters to compare with analog ones the last significant advantage of analog imo was being able to see the signal if it was changing over time e g checking electrolytic capacitors anymore most dmm have bargraphs etc that duplicate this thank you for your attention you could mail me your opinion at avm zeus tamu edu or open a discussion here i would appreciate either way alexander v mamishev power system automation laboratory phone office department of electrical engineering phone home texas a m university fax college station tx usa internet avm zeus tamu edu jeff gruszynski semiconductor test equipment systems engineer hewlett packard or t jeff hpmvd nsr hp com jeff hpuplca nsr hp com
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arcade style buttons and joysticks hi there can anyone tell me where it is possible to purchase controls found on most arcade style games many projects i am working on would be greatly augmented if i could implement them thanx in advance dave dnewman lynx dac northeastern edu
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re analog switches balanced demodulators in article msf skaro msf skaro as arizona edu michael fulbright writes i am trying to build a synchronous demodulator and i ve hit a snag in my application i want to be able to change the gain of an op amp amplifier from to controlable via a digital input the most obvious way i ve come up with is to use analog switches to adjust the gain of the op amp the only analog switch i have experience with it the unfortunately i want to switch an ac signal which goes from about v to v and the is only for positive signals i have a carrier signal which varies between v and v i want to demodulate an input signal by feeding the input signal thru a amp with a gain of when the carrier is at v and thru a amp with a gain of when the carrier is v the output is then low pass filtered i believe this is called lock in detection as well as synchronous demodulation look at the this is a triple to transmission gate analog multiplexer with positive and negative power supplies can be run from a single ended supply as well with dual supplies the logic inputs still range from ground volts to vdd this is a neat well i think so design for a switchable polarity amplifier input opamp output control x analog switch gnd all resistors are equal value when the analog switch is closed the amp is inverting gain of one with the switch open it is non inverting gain of one you can clean up the circuit to trim out input offset current if this hurts the balance this would show up as carrier feed through for high frequencies the slew rate of the opamp might cause problems especially if it isn t symmetrical and it usually isn t paul elliott dsc optilink petaluma ca usa uunet pyramid tekbspa optilink elliott or elliott optilink com i used to think i was indecisive but now i m not so sure
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re hc public domain software doesn t motorola amcu have something on the bbs yet
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re how to the disks copy protected in apr reed edu mblock reed edu matt block writes in article sehari marge ecss iastate edu sehari iastate edu babak sehari writes i was wondering what copy protection techniques are avaliable and how effective are they has anyone have any experience in this area with highest regards babak sehari uh oh umm there are a number of copy protection schemes some involve modifying the physical media and some involve encryption schemes c all of the ones that have existed over the course of computing have been successful for a time i recall however near monthly releases of new ways to crack the copy protection scheme of the latest releases the fact is none of them are completely secure or anywhere near it some are more or less difficult to crack and some have already been cracked i guess what i am saying is that your question is difficult if not impossible to answer what exactly do you want to know do you need a good one for a project you are working on how secure must it be are you trying to crack one that someone else has used i can probably make suggestions assuming the activity is strictly legal in general it is a bad idea legally to tamper with copy protection it can also lead to corruption of files which you necessarily do not have back ups of being as they are copy protected which can be devestating do you have absolutely no ideas for practical applications and are merely curious please clear up those questions and i ll try to help as much as i can incidentally the uh oh at the top is indicative of the dread anyone who has watched their friends hacking equipment be carted off feels when they are asked how to hack the area you are broaching is wrought with dangers many of which include breaking the law or at least addressing it from one side or the other matt i have written a program and i want to market it i would like certain degree of protection since my main custmers are individuals and not the cooperations i know laser hole burning method and hardware key method however my software is going to cost only so i can not afford that also at this low price i can not afford people make too many copy of my software well i guess say upto illigal copying is ok by me however i do not want someone to get a copy of pctools and copy my software off course i never meant to forbid the true hackers from copying since they can develope a better program anyway with highest regards babak sehari
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re power signal surges in home in article apr mprgate mpr ca vanderby mprgate mpr ca david vanderbyl writes kludge grissom larc nasa gov scott dorsey writes my car unfortunately has so much computer junk under the hood that it s astonishingly sensitive to rfi hmmmmm this has possibilities if the police are in pursuit of a vehicle maybe they can bombard it with high energy rfi right so all the cops will be buying antique muscle cars for chase cars otherwise the police cars will die too to get the attention of a large animal be it an elephant or a bureaucracy it helps to know what george patterson part of it feels pain be very sure though that you want its full attention kelvin throop
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re building a uv flashlight john hawkinson jhawk panix com wrote yes i know it sounds crazy call it an urge call it what you want just don t ask why anyway i d like to build a uv flashlight cheaply flashlight means it should be reasonably portable but could have a power pack if necessary my main question is the bulb where can i get uv bulbs do they need a lot of power etc etc i m not too concerned with whether it s long wave or short wave but hey if anyone has a cheap source of bulbs i ll take both check out a medical supply catalog the thing you are looking for is called a woods lamp so you can check for woods sign certain skin conditions flourecse sp under uv light they come in disposable penlight like types and larger ac powered types it is also used in eye examinations a flourescent dye is introduced to the surface of the eye then uv is shined on it shows up scratches and abrasions very clearly that would otherwise be very difficult to detect for the completest the dye is called flouescien and in normal light appears orangish and leaves a mild burning sensation to the eye for minutes until the tears flush it all out have fun dale farmer
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negative logic high this may sound like a simple minded question but this is the first time i ve ever had a need for this i ve been designing some relatively simple chip circuits based on things like photoresistors you know no light to photoresistor emit a logic high etc anyway i ve got some servos lying around and i wanted to do some things with them using digital logic i know all about having to pulse the signal and everything i just have one problem i m assuming i need a negative yes negative logic high to get the thing to turn in the direction opposite the direction it would turn under normal logic high is a negative logic high i ve seen this in schematics the same thing as an active low or what i m not using a bi polar power source so how would i get a negative logic high out of this thing i need to have all three signals available logic high logic low and negative logic high any help would be greatly appreciated also please reply via email as i never seem to have time to read this or any other group lately thanks much mark umlangston memstvx memst edu
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re adcom gtp ii ir sensor repeater spec s in article r innijp hp col col hp com johnr col hp com john t rasper writes does anyone know the details of the interface wire din for the ir remote sensor wire ir repeater for the adcom gtp ii preamp the adcom part numbers are the xr ii spm ii and ira ii a cursory physical examination of the pre amp connector indicates that the connector pin din may provide viewed from connector front pin v ma pin v ma pin signal ground pin demodulated signal v pp polarity ma drive pin signal to drive repeater led drives through ohm resistor v pp i assume that the repeater connectors mini plugs drive the ir repeater led s directly true can anyone fill in the s thanks here s the scoop when you get your home brew receiver working would you be willing to share it with the rest of us i always wanted to build my own but never have the time to fool around and design it pin signal ground pin signal pin always hot volts pin volts hot only when preamp is turned on pin infrared repeater connectors the infrared repeater jacks on the back of the preamp are not connected to anything inside the preamp except the pin connector pin there is a ohm resistor between the two jacks with a k from pin to ground the signal pin in the preamp is summed with the built in ir receiver they use a chip called cx a and a bjt to amplify the signal i would imagine the logical way would be to duplicate this circuit and use it as the external receiver if you need more info let me know randy randyd csd csd uwm edu
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re radar detector detectors are any brands quieter than others yes some radar detectors are less detectable by radar detector detectors i have a bel i just looked at the manual yesterday and it does indeed claim to be undetectable by rdd s pat
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re a and compatibility in article c owvs pr world std com internet surfer writes does any one know if the is timing pin compatible with the no the a is able to operate in a mhz system the can only take mhz without problems if you see a made by mos or csg take it its a a it seems the has in iheirent bug with cts rts handshaking and i need a suitable pin replacement to put in my serial card possibly a buffered version perhaps i know no fixed version of the there are different possibilities to work around this bug the easiest is to tie cts to gnd and use dsr or dcd as cts it should be easy to fix the software dsr is bit and dcd ist bit of the status register read with rs low and rs high using the cts line can lead into big trouble the instantly stops transmission if cts goes high this means that you may get only a half byte gerrit gerrit heitsch moenchweg holzgerlingen germany logical adresses uucp gerrit laosinh stgt sub org fido if we will ever be visited by aliens it will be very hard to explain why a lifeform that is intelligent enough to build atomic weapons can be stupid enough to do it taken from geo special about space page
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re what s a good ic for rs ttl signals in article c nz z scraps uucp frank holden ka uww writes i m looking for an ic that will convert rs voltage levels to ttl voltage levels something relatively inexpensive would be nice too anyone have a suggestion thanks well it looks as if digi key sells a chip with the number icl that does what you want they are selling it for about are you sure that he needs a two way converter if he wants only rs ttl i would suggest the mc its very cheap dm in germany this chip needs only v the mc ttl rs converter uses v and v btw the max and compatibles seem to be expensive in the usa i paid dm for a its made by harris its absolutely compatible with the max or the icl gerrit gerrit heitsch moenchweg holzgerlingen germany logical adresses uucp gerrit laosinh stgt sub org fido if we will ever be visited by aliens it will be very hard to explain why a lifeform that is intelligent enough to build atomic weapons can be stupid enough to do it taken from geo special about space page
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re electronic parts in nyc in fritzm apr sun panix com fritzm panix com fritz mueller writes i just moved to nyc and wondered if there are any electronics hackers out there who could point me to places in nyc that sell individual electronic components switches pots transformers caps try cables and chips let me dig out a reciept here we are cables chips at fulton street that s near south street seaport and wall street phone is and however when ordering there be very exact or there s a good chance they ll screw up otherwise they re pretty good and they deliver too cheers rob robert s mah voice every day an adventure one step beyond email rmah panix com every moment a challenge
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electronic parts in nyc hey all i just moved to nyc and wondered if there are any electronics hackers out there who could point me to places in nyc that sell individual electronic components switches pots transformers caps transistors etc radio shack doesn t count they have almost no selection and their prices are outrageous i have particular interest in audio components amplifier ic s power mosfets output transformers tubes and tube sockets pan pots faders etc i have checked out a lot of th street and canal street so far with no luck am i missing places looking in the wrong place or do i have to resort to mail order thanks in advance fritzm
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re decoupling caps onboard in article apr jarvis csri toronto edu ravin eecg toronto edu govindan ravindran writes i would like to know if any one had any experience with having on board decoupling capacitors inside a cmos chip for the power lines say i have a lot of space left im my pad limited design any data on the effect of oxide breakdown any info or pointers are appreciated dec did this on their new alpha chip i m sure you could call them up and ask them how they did it haha actually there are some details in their article in ieee journal of solid state circuits i think it was sometime around nov andy s
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re how to the disks copy protected in article sehari du cc iastate edu sehari iastate edu babak sehari writes i have written a program and i want to market it i would like certain degree of protection since my main custmers are individuals and not the cooperations i know laser hole burning method and hardware key method however my software is going to cost only so i can not afford that also at this low price i can not afford people make too many copy of my software well i guess say upto illigal copying is ok by me however i do not want someone to get a copy of pctools and copy my software off course i never meant to forbid the true hackers from copying since they can develope a better program anyway i wouldn t bother with the copy protection if i were you if you program is any good the pirates will have stripped the protection and will be distributing the stripped version is well under a week hardware methods prevent j random loser from using his copy ii pc to pirate your software but doesn t stop anyone who knows a few people with enough connections to real pirates who will be able to defeat your check for the hole code you may want to price your software depending on what it is a tad higher a price change from to probably would turn off very few potentials buyers and that way you could tolerate more pirates whose numbers don t change with the price as for the pirating figure ha ha of course a lot of pirates just have this thing about having pirated software even if they never use it so perhaps that really wouldn t count towards even so is awfully low joel kolstad p s i assume you re talking pc software if you re talking unix hp or something else somewhat obscure copy protection might be a slightly more viable alternative
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re dayton hamfest i booked a hotel red roof inn last week in cincinnati blue ash which is at the northern tip of the metro cincy area i chose it for a few reasons all hotels in and near dayton were booked solid this hotel is only costing night it was one of about rooms left on the night i reserved cincinnati probably has more to to at night than dayton i intend to hit the riverboat entertainment at dusk if anyone has other suggestions for nightlife please let me know of other hot spots thanks mark
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re need to find out number to a phone line alee ecs umass edu writes greetings situation i have a phone jack mounted on a wall i don t know the number of the line and i don t want to call up the operator to place a trace on it question is there a certain device out there that i can use to find out the number to the line thanks for any response al dial and it sound tell you the number skipper traider ersys edmonton ab ca mark bevan traiders of the lost arc edmonton alberta canada
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coil hey everyone i m new to this newsgroup so please excuse me if this is a dumb question i want to build a crossover for my stereo and i need a coil with an inductance of mh actually i need i was wondering if anyone knew where i could buy these or how to make these i ve called many places and no one i can find sells them if you have the answers just e mail me thanks in advance chris
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re a question about vac outlet wiring jeh cmkrnl com writes hmmm how are those orange isolated ground outlets often used in computer rooms wired they require two separate grounds one ground goes to the ground pin of the outlet and the other ground wire is connected to the outlet s mounting tabs and thus grounds the box and faceplate screw and metal faceplate if any the box faceplate ground goes to the normal distribution panel ground the outlet ground pin wire is generally connected to an insulated busbar in the distribution panel which is in turn connected to the building entrance main ground by its own wire so the two separate ground systems are connected together at the building s service entrance but one is also connected to every grounded piece of electrical equipment in the whole building while the isolated ground is shared only by the equipment plugged into isolated ground outlets of that panel if someone happens to accidentally short one phase of a v feeder to ground the main building ground is likely to have a lot of noise on it until the breaker trips or the fuse blows while the isolated ground will remain relatively noise free
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re looking for electronics dept info in austrailia hjkim hyowon pusan ac kr hojoong kim writes hi netters i am looking for the list of universities in austrailia which has electronics department i am considering to spend a year for research in austrailia about communication area i am interested in mobile communication areas and spread spectrum communications etc but i don t have any information about austrailian universities can anybody recommend a good university in co mmunic ation area any comments will be welcomed can i suggest the university of western australia in perth the weathers great the people are great and our electronic engineering department is great i am a first year student here so i don t know much about what projects but i do know they have a good reputation in the fields of dsp and communications ever heard of qpsx the people who own are ex uwa so that gives an indication of what the department is like for more information email yianni swanee ee uwa edu au with the above request and he should be able to tell some more info or write department of electrical and electronic engineering university of western australia stirling highway crawley western australia australia yours mark mtearle tartarus uwa edu au mark tearle email mtearle tartarus uwa edu au
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re need to find out number to a phone line well here in australia you dial to get the number read back to you if you live in the country include the area code of the nearest capital city eg for wa yours mark mark tearle email mtearle tartarus uwa edu au
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re atari processors in article pca psuvm psu edu pca psuvm psu edu writes does anyone know what processor the atari used what i m looking for is th e pin outs for the atari the schematics for it it does anyone have any idea where i could find this or any related information this is very impor tant also are the rom chips that were used fo rthe games still available or were they propreitary please email me with any responces as this is very important thanks a million btw anyone who works has worked for atari i could really use your help with i nfo on the old please email me if you are willing to help me thatnks alot peter the atari used a cpu just like their entire bit line xe xe computers as well as the game machine the had some extra asic chips that were basically modified graphics chips and pia s for the joysticks later model might have incorporated many of the chips into one asci as the weight of the machines and part count decreased a lot over the years additionally i think the used k k and up to k of rom for their games i have no idea how much ram it had to work with but i would hazard a guess of or k ram think comes from a lot of hacking with the and xe computers and occasionally hacking with the fixing it for monitor composite video use and audio hookups also i tryed to make a cartridge less system that stored the rom into a ram cartridge that could be loaded up at some prior time a way to backup cartridges i ve heard of a setup like this where games could be bought cheaply on fsk recorded tapes then you would load them into a special ram cartidge and play them anyways if you re interested in looking for equipment we ve got two machines around one composite a v modified and lotsa cartridges willing to sell for reasonable offer shipping and handling don t play it anymore since going to computers nintendo interested in that too hope that helps your question i might grab some s out too since they must be fun to play with as microcontrollers shishin squish yamada squish endor harvard edu
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re electronic parts in nyc there are also a couple or three places on west th between fifth and sixth harvey harvey fishman fishman panix com you don t get smart except by asking stupid questions
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re how to the disks copy protected in article apr reed edu mblock reed edu matt block writes i guess what i am saying is that your question is difficult if not impossible to answer what exactly do you want to know do you need a good one for a project you are working on how secure must it be are you trying to crack one that someone else has used i can probably make suggestions assuming the activity is strictly legal in general it is a bad idea legally to tamper with copy protection it can also lead to corruption of files which you necessarily do not have back ups of being as they are copy protected which can be devestating do you have absolutely no ideas for practical applications and are merely curious please clear up those questions and i ll try to help as much as i can may we interpret this as an offer to volunteer as editor for a copy protection faq i am quite sure that i am not alone welcoming such an initiative i will volunteer to ask some of the questions if you will provide the answers ketil albertsen
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magstrip card reader info can somebody please help me with information about an american magnetics corporation magstripe card reader that i recently bought locally from a surplus dealer on the rear it has the following information american magnetics corporation carson ca usa magstripe card reader model p n it is fitted with a cable with a rs cannon pin connector on the end and has a separate power connector like the once used with wall chargers frode frode weierud phone cern sl fax ch geneva e mail frode dxcern cern ch switzerland or weierud cernvm cern ch
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re electronic parts in nyc taft electronics th street between th th the only one left in what was once an entire district of electronics stores a little expensive trans am electronics canal street near th ave lots of surplus type stuff several other electronics or surplus type places are still on canal street i think bronx wholesale radio is still in business fordham road not too far from arthur avenue in the bronx also in the bronx is northeastern or was it northwestern northeast electronics on jerome avenue near bedford park boulevard they re mostly a tv parts supply house but when i was building cb radio projects they were quite handy ed ravin a tv cop fires a gun three times an hour a real cop prodigy services co fires a gun only once every five years white plains ny d i s c l a i m e r w a s h e r e elr trintex uucp or elr trintex uunet uu net
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speaker impedance help needed i want to connect a very small home made speaker up to the headphone jack on my macintosh lc for an experiment the dc resistance of the speaker is ohm any ideas how i can do this safely i think i need some kind of an impedance transformer or something tony wayne uva school virginia edu
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fet trons sp has anyone ever heard of fet trons or is it fetrons fettrons these were fet replacement modules for vacuum tubes i m looking for applications where they were used charlie brett hp ft collins
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re los angeles freeway traffic reports while driving through the middle of nowhere i picked up knbr am a clear channel station based in los angeles they had an ad claiming that they were able to get traffic flow information from all of the thousands of traffic sensors that caltrans has placed under the pavement does caltrans sell this info does knbr have an exclusive what s the deal doug former l a commuter claar you were right the second time it is knx believe it or not i also listen to knx in the evenings here in colorado it s kind of fun driving through the country listening to traffic jams on the back to your original question yes there are sensors just past every on ramp and off ramp on the freeways they re the same sensors used at most stoplights now coils in the pavement you might want to give caltrans a call or even ask bill keene knx s traffic reporter i doubt if just anyone can get the information but it would be worth asking just in case you can get it charlie brett former la commuter ft collins co
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radio electronics free information card how does the radio electronics free information cards work do they just send you some general information about the companies that advertise in their magazine or does it also give you sign you up for a catalog neil gandler
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re subliminal message flashing on tv kennehra logic camp clarkson edu rich theman kennehan says hi i was doing research on subliminal suggestion for a psychology paper and i read that one researcher flashed hidden messages on the tv screen at ths of a second is that possible i thought the take a look over in alt folklore urban there is a thread about subliminal messages on tv the fact that subliminal messages don t work aside an image can t be flashed on a tv screen fast enough to not be noticed bob billson kc wz internet bob kc wz bubble org nail bates way westfield nj uucp uunet kc wz bob friends don t let friends run dos microware
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re laser vs bubblejet fyi the actual horizontal dot placement resoution of an hp deskjet is th inch the electronics and dynamics of the ink cartridge however limit you to generating dots at per inch on almost any paper the ink wicks more than th inch anyway the method of depositing and fusing toner of a laster printer results in much less spread than ink drop technology it doesn t take much investigation to see that the mechanical and electronic complement of a laser printer is more complex than inexpensive ink jet printers recall also that laser printers offer a much higher throughput ppm for a laser versus about ppm for an ink jet printer something else to think about is the cost of consumables over the life of the printer a page yield toner cartridge is about us at discount while hp high capacity page yield cartridges are about us at discount it could be that over the life cycle of the printer that consumables for laser printers are less than ink jet printers it is getting progressively closer between the two technologies laser printers are usually desinged for higher duty cycles in pages per month and longer product replacement cycles bill mayhew neoucom computer services department rootstown oh usa phone wtm uhura neoucom edu n wed
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radar detector detectors several years back one of the radar detectors manufacturers in defiance to virginia s law against radar detectors passed out thousands of fake cardboard radar detectors at truck stops near the virginia state lines at that time there were no radar detector detectors i am not sure of the impact but i would imagine that enforcement of the law by visually sighting a radar detector became difficult if not impossible as i said earlier efforts to throw out or eliminate the va law against radar detectors has been in vain in fact effective jan the fine for possession of a radar detector accessable to the driver of a vehicle in va is now i have noted an interesting anomality with my alinco dr meter ham transceiver it will make a cheap radar detector scream i am not sure of the range but it is obvious by the brake lights that it can be at least feet at watts randy t agee wb bzx at some point you probably pondered the p o box th floor meaning of life and you came up with a virginia department of education satisfactory answer which has or has not richmond va stood the test of time or you shrugged phone mightily muttered beats the heck out of ragee vdoe vak ed edu me and ordered a cheeseburger
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re how to the disks copy protected write a good manual to go with the software the hassle of photocopying the manual is offset by simplicity of purchasing the package for only also consider offering an inexpensive but attractive perc for registered users for instance a coffee mug you could produce and mail the incentive for a couple of dollars so consider pricing the product at you re lucky if only of the instances of your program in use are non licensed users the best approach is to estimate your loss and accomodate that into your price structure sure it hurts legitimate users but too bad retailers have to charge off loss to shoplifters onto paying customers the software industry is the same unless your product is exceptionally unique using an ostensibly copy proof disk will just send your customers to the competetion bill mayhew neoucom computer services department rootstown oh usa phone wtm uhura neoucom edu n wed
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rpm floopy drives update many thanks to those who replied to my appeal for info on a drive i have which is rpm i now have some information on how to modify this for use with a bbc b computer not only do you have to change the speed from to rpm tried that but also change components in the rec play section to allow for the lower data rate kbit not kbit as it was designed for and also change the recording current to allow for the low data rate rev speed hopefully this should sort it all out not bad for quid normally quid and upwards the drive is a jvc mdp series drive michael brown csulo csv warwick ac uk mjb dcs warwick ac uk lost interest it s so bad i ve lost apathy
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re how to the disks copy protected in apr w lumina edb tih no ketil edb tih no ketil albertsen tih writes may we interpret this as an offer to volunteer as editor for a copy protection faq i am quite sure that i am not alone welcoming such an initiative i will volunteer to ask some of the questions if you will provide the answers ok here could be the first question or answer or something q i want to copyprotect a program i wrote how should i do it a you would be wise not to copyprotect that program you see those people that wants to get a cracked copy of your program will go to various length to crack your program and some of those crackers are good and know the common tricks so the copy protection wouldn t stop those ok then what about legitimate users copy protection can be a hassle for legitimate users and can hinder them in their work expecially if there is some key item that can get lost so the copy protection wouldn t help much of the legitimate users but would make life somewhat of a misery for them this is my opinion and i speak as a legitimate user you are of course free to have your opinion about this subject einari rhi hi is
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re long distance ir detection in article apr dres dnd ca sburton dres dnd ca stan burton writes i would like to be able to detect the angular position low accuracy of an ir emitting source at a distance of about meters more is better in daylight the ir source could be emitting a signature i m leaning toward khz square wave with duty cycle i am considering the use of a quadrant detector from centronic inc to give information to a pan tilt head to point the sensor and thus determine the angles for the source i am considering wazing the heck out of an ir led s possibly an optek op or motorola mled wazing would mean at least amp current pulses at this current the duty cycle of the led drops to and i would need to cycle five of them in turn to get the required has anyone done something like this why don t you just run one led at khz and use a flip flop at the receiving end to divide by and give you a good square khz signal just a thought lori stan burton dnd crad dres dtd mss agcg sburton dres dnd ca dre suffield box medicine hat ab canada t a k red fishy wins lori gardi ext dept of astronomy lgardi uwovax uwo ca university of western ontario london on canada n a k
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wireless data transfer i am involved with a michigan company that has an application requiring wireless data transfer if you have expertise or information that may assist us in this project please contact me internet leblanc cvm msu edu
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x oversampling cd player hello i just bought a new portable cd player for the office and i notice that it proudly proclaims times oversampling on the box now while i think i understand what oversampling is the rate of discrete samples exceeds the highest frequency component of interest by some factor i don t understand this times business it seems to me that when i bought my first cd player was it really years ago the specs said times could someone please tell me whether i m getting senile if i m not then what good does it do for the player to take samples at a higher rate if i really wanted better fidelity wouldn t i have to have the same higher rate of sampling during the recording process furthermore am i wrong in interpreting the sampling rate from the player s point of view as being the same thing as the data rate for the bit stream coming off the optical medium does this mean that the data rate related to the rotational speed of the disk has changed since i m so confused cliff clifford bowman box russellville ar hcb netcom com i m pretty sure the world isn t fair if it were i d be a lot worse off n tju
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re los angeles freeway traffic reports in article c ulqn gpw fc hp com cfb fc hp com charlie brett writes while driving through the middle of nowhere i picked up knx am a clear channel station based in los angeles they had an ad claiming that they were able to get traffic flow information from all of the thousands of traffic sensors that caltrans has placed under the pavement does caltrans sell this info does knx have an exclusive what s the deal well they claim they are the only radio broadcaster with this information but the city s cable channel in cablevision areas shows this information map during travel times am and pm i believe most of the major la freeways are covered the computer generated map shows green yellow red or flashing red respectively mph mph mph and incident i might be off a little on the speeds since this is from memory i often look at this display in the morning to see if i really want to fight the traffic on the sepulveda pass or work from home for a little while to wait for it to clear another poster explained the origin of the information sensors embedded wire loops in the pavement near ramps and every half mile or so caltrans has had a big board driven from this data in their traffic control center for some time i don t know if they are selling the data or if anyone with the equipment necessary for its transmission and display can have it ed hall edhall rand org
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re help how to construct home built battery for rd grade sci report in article c ge lo athena cs uga edu mcovingt aisun ai uga edu michael covington writes almost any two dissimilar metals in almost any electrically conductive liquid example copper and zinc in coca cola copper and galvanized steel nails in a lemon don t expect much power out but it should be easily detectable with a voltmeter michael a covington associate research scientist artificial intelligence programs mcovingt ai uga edu the university of georgia phone athens georgia u s a amateur radio n tmi a copper and a zinc rod in a potato also work nice
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hi volt from battery i need a small battery powered hi voltage capacitive discharge supply to deliver joules at volts this implies a uf cap i have built a very satisfactorily operating version from a max but do not like the idea of using a single source part it seems that the ubiquitous camera flash circuit is what i want but i cant get mine apart without breaking it i would appreciate receiving the circuit description or a source of one i have already looked in several electronics circuits handbooks to no avail thanx martin johnson martyj uiuc edu mind your business on first us coin
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re arcade style buttons and joysticks in article apr lynx dac northeastern edu dnewman lynx dac northeastern edu david f newman writes hi there can anyone tell me where it is possible to purchase controls found on most arcade style games many projects i am working on would be greatly augmented if i could implement them thanx in advance hap controls just outside chicago sells these i don t remember which suburb they are in the prices are pretty reasonable and they are easy to hook up i bought a new coin mechanism from them for a couple of years ago andrew macrae
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re suggestions on audio relays in article c qsbf iek ms uky edu billq ms uky edu billy quinn writes i built a little project using the radio shack vdc relays to switch audio i got pretty bad clicks when the thing switched is there a good relay relay circuit that i can use for switching audio so that there will be no noise of any kind on the audio lines with relays alone you will always get a transient when you abruptly turn on or off any channel if you don t want to hear the transient use some other device a photoresistor output optoisolator is the usual sort of thing to gently mute the signal then switch then remove the power from the lamp in the optoisolator it used to be standard practice to employ photoresistors in switching audio because the photoresistor time delay a few thousandths of a second kept any noise in the digital side which drives the lamp from contaminating the audio and the devices are cheaper than relays john whitmore
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re radar detector detectors in article apr rapnet sanders lockheed com babb rapnet sanders lockheed com scott babb writes brian day bday lambda msfc nasa gov wrote on december it was illegal to operate a radar detector in the state of virginia if one got caught one got fined the federal communications act of made it legal for you to operate a radio receiver of any kind on any frequency including x k and ka bands in the united states and the commonwealth of virginia has not exactly butted against the issue on those grounds the claim is that as a matter of traffic safety one is not allowed to have a functioning radar detector on the dashboard while operating a motor vehicle yes the argument is bogus but it hasn t been successfully challenged in court yet john whitmore
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re need to find out number to a phone line try finding a friend that has caller id then give him a call jb in article bd dea ecs umass edu alee ecs umass edu writes path shearson com uupsi psinntp uunet haven umd edu darwin sura net newsserver jvnc net howland reston ans net noc near net nic umass edu risky ecs umass edu umaecs alee from alee ecs umass edu newsgroups sci electronics date apr gmt lines greetings situation i have a phone jack mounted on a wall i don t know the number of the line and i don t want to call up the operator to place a trace on it question is there a certain device out there that i can use to find out the number to the line thanks for any response al joe bore life is short code hard jbore shearson com uunet shearson com jbore beeper
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re power signal surges in home vanderby mprgate mpr ca david vanderbyl writes drand spinner osf org douglas s rand writes hams can legally run up to watts it is very unlikely however that a ham would be running that kind of power from a car not possible either you d need about a amp alternator for just the amplifier it is too possible as the original poster said it is very unlikely but definately possible can you say batteries i ve even seen pictures of an installation where the ham pulled a little trailer behind his car with a kw generator and ran the full legal limit while mobile i don t know what his gas mileage was like though or where he found resonators able to stand the gaff emd ham almanac bc ca robert smits ladysmith bc
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re a question about vac outlet wiring crichmon sedona intel com chris richmond writes well my house was built just last year and the breaker box is wired the same way all the white and ground wires are on a common bus except for the v circuits only black wires are hooked to the breakers it was the same way in the last two houses i had also are you sure this is wrong i still have the building inspector s signature on the breaker box the point is that the original poster was talking about connecting ground and neutral in the outlet box big no no and you are talking about them being connected in the breaker box as things should be if this is not obvious the point is that there should be current flow in the white i e neutral return wires when things in the house are operating there should not be any flow in the ground wires unless there is a fault condition notice also that in the breaker box there is a wire leading from the above mentioned junction to earth ground usually a pipe or spike driven into the ground tom trebisky ttrebisky as arizona edu
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re x oversampling cd player in article hcbc un l dd netcom com hcb netcom com h c bowman writes hello i just bought a new portable cd player for the office and i notice that it proudly proclaims times oversampling on the box now while i think i understand what oversampling is the rate of discrete samples exceeds the highest frequency component of interest by some factor i don t understand this times business it seems to me that when i bought my first cd player was it really years ago the specs said times could someone please tell me whether i m getting senile if i m not then what good does it do for the player to take samples at a higher rate if i really wanted better fidelity wouldn t i have to have the same higher rate of sampling during the recording process furthermore am i wrong in interpreting the sampling rate from the player s point of view as being the same thing as the data rate for the bit stream coming off the optical medium does this mean that the data rate related to the rotational speed of the disk has changed since note i just tried to figure this stuff out about a month ago myself from various people on the net so i could be wrong the data is only ever read once barring mistracks and such of course and eventually gets turned into khz bit two channel data oversampling takes two discrete data points and interpolates n points between them for n times oversampling when i asked people said that the interpolation was not simply linear interpolation but significantly more complicated anyway then the purpose of oversampling is to move the effective sampling rate up to n times khz in order to use higher frequency antialiasing filters for the same quality filter higher oversampling lets you build cheaper filters whereas for the same price filter higher oversamplings lets you build better filters so assuming the quality of all other components in a cd player remained the same oversampling should allow a manufacturer to produce slightly better sound due to anti alias filtering joel kolstad
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re suggestions on audio relays in article apr mala bc ca wagner mala bc ca tom wagner wizzard of old audio visual equipment nanaimo campus writes in article c r r id megatest com alung megatest com aaron lung writes in article c qsbf iek ms uky edu billq ms uky edu billy quinn writes i built a little project using the radio shack vdc relays to switch audio i got pretty bad clicks when the thing switched i was doing my question is is there a good relay relay circuit that i can use for switching audio so that there will be no noise of any kind on the audio lines are you switching high level signals or low level signals like pre amp a novel circuit i used to build was a primitive optical isolator it consists of a resistive photocell and a lamp all packaged in a tube when the lamp is off the cell is high resistance turn the lamp on and the resistance lowers i use an h f fet optoisolater to switch microphone level signals there is no click since i put a uf cap across the led distortion measurement are very low with mic level and they went up to at a db line level all i did was put the fet in series with one leg of the balanced line no hums pops just audio jumping out of silence the fet runs about million ohms with the led dark and drops to ohms with it on hey it works and works well galen watts kf yj
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re how to the disks copy protected in article apr w lumina edb tih no ketil edb tih no ketil albertsen tih writes in article apr reed edu mblock reed edu matt block writes i guess what i am saying is that your question is difficult if not impossible to answer what exactly do you want to know do you need a good one for a project you are working on how secure must it be are you trying to crack one that someone else has used i can probably make suggestions assuming the activity is strictly legal in general it is a bad idea legally to tamper with copy protection it can also lead to corruption of files which you necessarily do not have back ups of being as they are copy protected which can be devestating do you have absolutely no ideas for practical applications and are merely curious please clear up those questions and i ll try to help as much as i can may we interpret this as an offer to volunteer as editor for a copy protection faq i am quite sure that i am not alone welcoming such an initiative i will volunteer to ask some of the questions if you will provide the answers ketil albertsen hey now will you stop encouraging him copy protection only serves one pur pose to keep the honest buyer from making legal backup copies it will definitely not stop any pirates if you want to protect you soft supply a good documentation and support this is imho the only way of effectively pro tecting software best regards arno arno schaefer ensimag e annee email schaefer silene imag fr tel no you re not paranoid the world is really out to get you
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re arcade style buttons and joysticks in article apr lynx dac northeastern edu dnewman lynx dac northeastern edu david f newman writes subject arcade style buttons and joysticks can anyone tell me where it is possible to purchase controls found on most arcade style games many projects i am working on would what about the common joystick found in all computer shops gerrit
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re beginner s rf in article c sr h jph cbnewsl cb att com klink cbnewsl cb att com steven r klinkner writes can anybody recommend a good application oriented beginner s reference to rf circuits steve klinkner at t bell labs srk boeing att com i have the arrl handbook for the radio amateur and i m getting the solid state design for the radio amateur the handbook is and solid state is from arrl main newington ct but you should be able to find them at electronics or amateur radio stores arrl will want or so for shipping good luck galen watts kf yj
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re hc public domain software in article murashiea mail beckman com writes does anyone know of an ftp site where i might find public domain software for the motorola hc microprocessor i am looking for a basic interpreter compilier or a c compiler thanks in advance ed murashie yep at oak oakland edu they have a couple different hc things in pub msdos emulators and get the file index txt for a list of what they have lige
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seeking info on wear on monitors we are dartmouth engineering students we are looking for documented data regarding the wear associated with turning on an off a monitor and how it relates to power consumption interested in a comparison between the wear on a monitor which is left on continuously and one which is turned off when not in use please personalize e mail to ds dartmouth edu thank you dan stern oliver weir
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re how to the disks copy protected in article apr uhura neoucom edu wtm uhura neoucom edu bill mayhew writes from wtm uhura neoucom edu bill mayhew subject re how to the disks copy protected date wed apr gmt write a good manual to go with the software the hassle of photocopying the manual is offset by simplicity of purchasing the package for only also consider offering an inexpensive but attractive perc for registered users for instance a coffee mug you could produce and mail the incentive for a couple of dollars so consider pricing the product at or documentation for the program a lot of shareware out there is very similar in the approach send in your money and you get documentation and a free upgrade to the latest version perhaps even support of some small degree whatever you want to offer that is better than the circulating version you re lucky if only of the instances of your program in use are non licensed users figure about as i have seen the best approach is to estimate your loss and accomodate that into your price structure sure it hurts legitimate users but too bad it doesn t really hurt legit users shareware is still much cheaper than the alternatives visit the sounding board bbs a wildcat bbs obdis all opinions are specifically disclaimed no one is responsible patrick taylor ericsson network systems thx exuptr exu ericsson se don t let the se fool you
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re what to do with old k simms in article netnews upenn edu jhaines eniac seas upenn edu jason haines writes i was wondering if people had any good uses for old k simms i have a bunch of them for the apple mac and i know lots of other people do to i have tried to sell them but have gotten no interest so if you have an inovative use or want to buy some simms sure i ll give you bucks for all of them
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exhausted student needing help well i ve now been working on this damned stepper controller board since pm it s now am i m pissed off period alright i can drive the steppers through the p s no problem that s with the wire steppers to and the other are the phase lines problem i ve got some wire steppers i put the darkest line to and the other to the p worked kinda tried it with a printer stepper moves the head back and forth wires didn t work too well it would shift back and forth use something like a instead also i ve been trying to get a bunch of npn s to work with it no luck tried pnp s still no luck i don t know if i m cursed on this or what but i feel my brain slowly frying with the thought of stepper arggg i don t know what s wrong with the transistor hook up to pkg type also tryed the n pkg type no luck i m going to try getting some z s and i hope you can help me with this problem if someone can please help me with this soon it would be greatly appreciated thanks inspiration comes to o baden sys bison mb ca those who baden inqmind bison mb ca seek the baden de bari unknown l
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re circuit cellar ink address in article qvlmainnhuu shelley u washington edu ptorre hardy u washington edu phil torre wrote is cci still published if so does anyone have their address circuit cellar inc park st suite vernon ct jeff babb babb sciences sdsu edu babb ucssun sdsu edu programmer sdsu larc
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beginner s rf can anybody recommend a good application oriented beginner s reference to rf circuits i am pretty good on theory know what different types of modulation mean but don t have a lot of practical experience a book detailing working circuits of different types modulation power frequency what is legal what is not et cetera would be very helpful thanks steve klinkner at t bell labs srk boeing att com att boeing srk
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