PhysicsProf Steven E. Jones circuit shows 8x overunity ?

[xee2]

I'm seeking the way to turn on/off transistor with minimal influence on transformer while still to sense the change to open transistor.

Short base to emitter.

[JouleSeeker]

  I have looked at the waveforms produced by the JT-variant by Xee2 (my build) -- see attached.  I have added a 1ohm R in series with the LED, and the waveform shows the voltage drop across this R:  V=IR = I since R=1.

Upper left shows one pair of pulses typical of operating in the region of interest (below the critical voltage as defined in my recent post above).  IOW, the LED has turned OFF and is now back ON.

Lower left expands the first pulse.
Right waveforms are of the right-most pulse of the pair; note that the right-most pulses differ, as seen by juxtapoing two observed waveforms.
Interesting (IMHO).

[xee2]

  I have looked at the waveforms produced by the JT-variant by Xee2 (my build) -- see attached.  I have added a 1ohm R in series with the LED, and the waveform shows the voltage drop across this R:  V=IR = I since R=1.

Upper left shows one pair of pulses typical of operating in the region of interest (below the critical voltage as defined in my recent post above).  IOW, the LED has turned OFF and is now back ON.

Lower left expands the first pulse.
Right waveforms are of the right-most pulse of the pair; note that the right-most pulses differ, as seen by juxtapoing two observed waveforms.
Interesting (IMHO).

I do not have a real scope (just a toy). But I have seen that there are often two pulses. This makes it hard to measure frequency without a scope (I would measure frequency by time between large pulses). I can not think of any reason why the waveform does not repeat.

[NickZ]

   @ JS:
  That effect may be caused by the pot.  Try a different one, of higher or lower value, I'll bet it goes out and on again at a different voltage. But, that may not be very important in relation to finding the sweet spot.

[nul-points]

 
Steven

i made an interesting discovery - the tertiary winding for the o/p in my previous circuit is  redundant!  (see below for updated schematic)

the latest circuit, using a 1000uF 35V cap as C2 (all other other parts as posted above) takes 687 seconds (11min 27sec) to discharge a nominal 1000uF cap from 2.55V to 1.5V

C2 1000uF (nominal)
2.55V => 3.251mJ
1.50V => 1.125mJ
                    -------
           Ein: 2.126mJ

Pav: 2.126/687 = 3.1uW (including cap leakage)


thanks
np


PS  if the 'blanking' voltage is different between two different coloured LEDs and nothing else changed in the circuit, presumably then it's related to the excitation levels involved in the different turn-on and forward-voltage drop characteristics of different colour LEDs?


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