cheap sub uH inductance meter?
I came up with this simple idea for someone with no instruments other than a PC to use as a stop watch.  Using NPO cermaic caps and small inductors, this is a fairly reliable oscillator that ought to be connected  with short leads.


Insert L 500nH  with short leads.
two 1000pF NPO/COG ceramic caps
NPN any General Purpose  (e.g. PN2222A )
3.6V LiPo or 5V regulator with decoupling caps.
two 74HC4060 CMOS ripple counters (not CD4060)  
LEDs and R's for clock timing with stopwatch or PC timer.

If you need help figuring out L from the C value and binary divider, just ask.  ... Q13 means 14th stage or divide by 2^14 or 16,384.  You could use decade counters as well.  Two such counters cascaded is 2^28 or /268,435,456.

This was just a quick and dirty solution.


The transistor Colpitts Oscillator works to over 100MHz may saturate and is not a pure sinewave but can be tweaked with the series R to prevent saturation (harmonics)

Using a known L value 1% and measure timer interval for 1% accuracy around 100 seconds.+/-1  thus 500nH with 1000pF (/2) gave me 10MHz so /268,435,456 = 26.8 second cycles.  The biggest limitation is the max clock speed of the 1st CMOS counter, usually around 25MHz at 3.6V or 85MHz at 5V.