Transistor assistance
I need to add a transistor to one of the pins I've programmed to push
  20mA to 7.5v.


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  what transistor will boost 20 milliamps to 7.5v?


Ampers can't be boosted to Volts!!!



--You must know the current consumed by the kanthol-wire by:

--first: measuring it's Resistance (R) using a MultiMeter... 

--after, you have to use the Ohm's law:

I = V/R

--with V=7.5V , and R measured in first step; let's say it's 30&Omega;, then:

I=V/R = 7.5 / 30 = 0.25 A

wich is 250mA

--the GPIO pin can only deliver 20mA, and you need to boost those 20mA to 250mA , and here is the function of the Transistor...



there are millions of transistors with millions of characteristics...
it's up to you to choose...









simulate this circuit &ndash; Schematic created using CircuitLab

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