Selfrunning cold electricity circuit from Dr.Stiffler

[retrod]

I don't have the fancy test equipment most of you have but I thought I would share my replication results. I built the Thomas driver replication this morning and as careful as I thought I was, nearly everything was put in backwards except the transistor  . After sorting thought it all it was working very nicely. I fiddled a bit more and managed to break the core in half! I then found that moving the core pieces helps to 'tune' the circuit.
My start voltage was 7.9 volts using a 9v radio battery, DC current measured 48ma. This curcuit was driving 38 bright white LED's. I made a YouTube video, you can see it at http://www.youtube.com/watch?v=kiIl722vK1s
I go off on a tangent after I discover a microphonic property of the circuit.
Enjoy,
Dave

[Pirate88179]

Great work Dave!  Nice discovery of the feedback effect.  What the heck could that be I wonder?  This is fascinating.

Bill

[Bruce_TPU]

@ Dave

Great video! 

The barium ferrite coil core is actually a tuning coil for an am radio.  So in my mind, not a mystery that another radio next to it would be effected.  BUT,    the feedback displayed makes me wonder if someone could put two of those cores into the circuit, and using a radio, attempt to tune each to feedback into the other.   

Cheers,
Bruce

[retrod]

Thanks guys. I'm working on the feedback 'thing' right now. I managed to pull both core segments out and to my surprise the LED's are lit as bright as ever. If I get the core close to the coil I can tune the circuit to fully quiet the radio. It's at that point the audio feedback starts and vibrates the whole radio. I took the back off the radio and almost every component makes a sound. The most sensitive area is near the main tuning cap of the radio. It may be nothing, I'll try it with another radio.

UPDATE: Well, I tried another radio and the same thing happens. I made a short video so you can hear it. This (Sears) radio has more heterodyne whistle but I'm sure you will be able to hear the audio type feedback as well. If I can build this circuit anybody can, lets see some more replications.
http://www.youtube.com/watch?v=gyCYqvE-APc

Dave

[MeggerMan]

@All,
It works (Thomas Oscillator) but no where near OU yet and I doubt my setup will get there.
Transistor is BC184L with a gain of about 240, circuit seems oscillate at about 12MHz.

Input is 9.2V x 6.2mA = 59mW
Output is 22.4V x 0.82mA = 18.3mW
Output is 8 white LEDs, 3.8V 30mA 13000mcd (I think they are all seconds - bought on ebay from Hong-Kong)
Therefore 32% efficient.

Yes sure, the LEDs look bright, but you can get a white LED to glow at 2.4V and 10uA = 24uW
This is a little different to the max output of 13 candles at 3.8V and 30mA = 114mW
I think I have got dazzled by looking directly into the LEDs

I was able to measure the output by using a 10uF 63V capacitor to supply the LEDs.
It would be interesting to see what results everyone else has achieved by measuring the input/output.

Next step is to try a toroidal core in place of the stick antenna to improve the efficiency.
There is no tuning option with a toroidal core, so I may need to add a tuning cap.





Regards
Rob