Now the question remains why?
Does the charging capability seems to decrease at night .. This could be because of less electric noise pollution from radiostations, mobilephones and so on at night
Best regards
beno
hi all
apologies for a marathon post here - i hope you will consider it all to be on-topic wrt recent posts
firstly, from observing my 'slower' variation of Steven's circuit (approx 25uS pulses with a very low 'mark-to-space' ratio, more like the Russian circuit) i see a decreasing amplitude 'sine'-like oscillation, approx 55kHz, immediately after the pulse
this sine wave is occurring when the system enters a high-impedance state when the 'driven' pulses stop - ie. no load, little dissipation
the wave usually decreases as a small amount of energy remaining in the self-resonant winding setup dissipates during each cycle
i've found that this waveform is significantly reduced or 'killed' by applying any load - the energy left in the system just dissipates more quickly
when i was experimenting with different forms of feedback in the last few days, i added a 'tuning' cap across the o/p winding (as per the Russian cct) and i could easily get the sine waveform to sustain for several seconds after the intended pulses had stopped (at the same amplitude, approx 1V) until the sine suddenly 'snapped' to off
interestingly, when i replaced the transistor base bias variable resistor (250K ohms) with a schottky diode (1N5187), using the reverse leakage of the diode as a very high impedance bias 'resistor', the circuit spontaneously started to produce this 55kHz sine wave of approx 250mV pk-pk (from cap charge alone) without ever getting into pulse generation mode
i watched it for several minutes to see if it started to decrease in amplitude and, if anything, it appeared to continuously fluctuate up & down slightly, without any obvious pattern
i suspect that these oscillators can operate in a very high-impedance mode (as if the whole circuit has a high 'Q' factor) and they can use remnant voltage in the system very efficiently
however, my requirement was to generate short bursts of pulsed energy which i could feedback into a NiMH cell, and since this 'continuous' wave couldn't provide sufficient amplitude or power to achieve this, i noted that this behaviour was interesting, but not useful to me at this time
i suspect that the Russian circuit is showing similar behaviour
my second comment, relating to all this, picks up on a couple of other investigations i've done - one a couple of years ago, monitoring the self-charge of capacitors, and the other an ongoing experiment with simple D-I-Y cells
in both these experiments i've recorded a daily fluctuation of self-charge of isolated (and enclosed in metal case) systems
the major correlation of the self-charge appears to be temperature, but other factors have appeared to contribute also, and sometimes these seem to link to astronomical conditions
in one test, i used a capacitor which previously had been shunted by a 1M ohm resistor for at least 6 months continuously
under these conditions the voltage on the cap had shown a continual cyclic positive charge of a few mV pk-pk
i removed the shunt resistor, replaced the cap in the metal case, and took 'spot' voltage measurements over the next few months
in the first couple of weeks, the voltage on the cap rose exponentially to somewhere in the region of 50-100mV, and then it settled into a linear increase with time
when i stopped monitoring the capacitor after about 6 months it had reached 300+mV
this was NOT because the capacitor was 'relaxing' back to a previous state of charge - it's maximum voltage for the previous 6 months was only a few mV!
details of all my test findings can be downloaded in PDF format from:
link-->
http://ringcomps.co.uk/doc/pages/secret_life_of_capacitors.pdf the D-I-Y cell experiment is interesting, not only because one cell appears to be self-sustaining (with a very small load) - several months achieved so far - but the cell voltages rise & fall with temperature
most of the cells i've made have had a positive temperature co-efficient (cell voltage increased with temperature rise) - and i expected that energy was being supplied to the cell with ambient heat enabling the voltage to rise on-load
however, the cell which is now self-sustaining shows an INVERSE temperature co-efficient!
(details via the Blog link below)
i can't explain that one - the load circuit is the same - the cell parts are the same materials (possibly very slight constructional method)
so - in both these cases the charge effect is different at night - but this is mainly because the temperature changes by a few degrees, compared to daytime
i don't rule out the possibility that these low-powered experiments are also being affected by cosmic particles - but i can certainly discount electromagnetic influence when the systems are operating inside e/m shielding
hope this has been helpful
np
http://docsfreelunch.blogspot.com