Saturday, October 14, 2017

Quick crystal tester

Needed a quick crystal tester, could had lash it up in a little piece of pcb but decided to give it a more robust look and leave it a bit more permanent case is needed again.
Circuit is out of ordinary/common ones and probably will not work with all crystals but for the intended ones it worked, if you replicate you might need a small 20pF cap in parallel with collector and emitter of the transistor, mine worked without.

Here's the outcome testing a crystal:





The counter is a pre-build module with VFD display, couldn't managed to take a decent picture of the display even with a better camera, I was not born to be a photographer...

The terminal connected to the battery was a left over from the exploded battery on the previous post, so some cents were saved.



Schematic:
output waveform:




Some more crystals in testing:

And more pictures:



Have a nice weekend!




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