No rocket science here, I just wanted to see how low can we go on voltage for a simple crystal oscillator.... following the idea of a possible solar cell powered beacon....
Schematic (from BITX transceiver):
Crystal connected directly to ground and I used 390pf capacitors...just run out of 220pf :) and the 120K replaced by an 100K resistor.
Transistor is the incredible 2N3904... what else!
And the lousy photo on the assembly, I used the AM modulator part from my laser experiments (an LM317 regulator)... without modulation of course...
Here the consumption at 1.78V:
..That's mA...
Didn't tried any lower voltage...
And with another voltages...
Emitter is connected to the high impedance input of the frequency counter
Just tested an 10Mhz crystal.
Have fun....
7 comments:
Nice test. I wonder for how low in voltage it would have worked? Maybe as low as the 1-1.5 Volt circuits Whatever happened to the 1 Volt QRP Transceivers?
Hello Sverre,
Thank you for the comment, I hadn't read your post before (what a coincidence, hi) but will follow the blog for sure.
I didn't tested lower voltages just because I was lazy and didn't bothered to change the voltage divider on the LM317 output.
http://www.swharden.com/blog/2010-05-24-solar-powered-qrss-beacon/
http://wa0uwh.blogspot.pt/2012/04/qrp-tests-for-night.html
I tested latter on with one of those garden solar cells but could not get a stable oscillation, probably will need 2 in parallel and series with another 2 to get more current and voltage.
tens de usar alguma coisa para armazenar a energia, se insistires em usar a corrente directamente dos paineis nao vais longe....
Imagina que passa uma nuvem !!!! a corrente baixa ;)
Viva Pedro,
Sim, tenho consciência do facto :)
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