5 May 2011

Ultra low voltage oscillators

Thinking a bit more about my crazy idea for a mains hum powered QPRp beacon TX, I chanced upon this page which discusses FETs running from extremely low voltage supplies. See http://www.dicks-website.eu/fetosc/enindex.htm. Some of the zero threshold voltage MOSFETs (ALD110900A) used in sensitive crystal sets may also be useful in this application. The link shows an FET oscillator powered by just a thermocouple producing only 13mV! Incredible. See also http://cap.ee.ic.ac.uk/~pdm97/powermems/2009/pdfs/papers/069_0209.pdf and http://www.aldinc.com/pdf/Ultra%20Low%20Power%20Oscillators.pdf


Bert, PA1B said...

Hello Roger, Thank you for the interesting websites. I read interesting website of Dick with its oscillator with J-FETs and a transformer. Dick has also other interesting things on his web-site if you click on "back to the index".
73, Bert

Michael, AA1TJ said...

Wow...very interesting reading, Roger. Thank you! By coincidence, my current project is a portable 20m CW transceiver intended to be powered by a candle-heated TEG.

In the past weeks I've worked across to Europe with the prototype XCVR running 80-90mW and a supply voltage of 1.40Vdc (although not yet candle-powered). The transmitter produces 10mW at a supply voltage of 0.87Vdc. Peter, DL3PB, has been "lighting the way" for me with his candle heated TEG experiments.

I intend to carry this radio on my walk across Austria next month. If I don't get the candle power working in time for the trip I'll simply use one "D" cell flashlight battery. Still, I've got my heart set on working "DX by candlelight."

Rog, I hope to work you (you too Bert!) next month as OE/AA1TJ.