[quote author="mediatechnology"]
I though it is a kind of noise measuring device, no?
Look at the polarity at the input of the "DMV."
(sic)
Where's that negative voltage coming from? No, I wasn't "DUI" when I drew that.
It's a voltage generator. Zenering the B-E junction makes photons and a photo diode out of the C-E junction. (At least we're led to believe.)
Glad you had a nice trip!
I hadn't been in the shop since posting this and there was that little tortured 2N3904 with the clip leads still connected. I gave it a good funeral.
[/quote]
What happened to it? Why funeral? What did you measure after torturing it? I used cb junctions for diodes, be junctions for Zeners developing hybrid ICs, but did not have a clue if breaking down a be junction causes any damage. At least, after measuring of breakdown voltages on a curve tracer transistors were still usable, especially well selected and matched ones!
It may be also a Hall or Peltier effect. If cooling a body helps to increase a voltage it may be a Peltier effect: collector has less thermal resistance with the body than emitter has.
I totally forgot physics of semiconductors that I knew excellent long time ago... Potential barriers... Energetic dips... Yes, generation of photons is possible, and it is possible that photons add some energy to electrons causing a negative potential on collector.
I like this idea, it is excellent, if opamps on the same crystal are identical! If not, at least input currents will be smaller!
http://electronicdesign.com/Files/29/6362/Figure_02.gif
But... One LED and couple of photo diodes will do the same trick. Even 3 identical LEDs will work well. I think of something similar to power electret mics from 48V phantom source (I want to build a phased mic array from cheap capsules).