Originally posted by ashtweth
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It looks as if your getting very close just as I did at first with this small but complex circuit .... well done my friends
The 555 timer does look a little warm but if your following the revised August 12, 2009 Rosemary Ainslie COP>17 Heater Circuit there are several changes that I have made that makes a big difference or will as soon as the equipment is possibly available again for me.
The added 4k ohms at the 555 positive rail was only for the "Ainslie - Murakami Negitive Dominant Waveform Generator Circuit" and is not used for the "Rosemary Ainslie COP>17 Heater Circuit" sorry for any confusion here with two circuits ......
1) The Gate pot was a 5k ohm 10-turn and now needs to be a 10 ohm multi turn potentiometer (15-25 turn ) so that using a DMM or equivalent be able to adjust to 6.0 to 5.0 using the 32mm prototype "Quantum" load resistor.
A digital Multi Meter or bench top unit able to see 00.00 type ohms not just tenths but hundreds to get the sweet spot of 5.80 to 5.30 ohms (checking pot back lash) and using a second DMM monitoring the highest voltage reading from your 24 volt battery bank while doing the gate pot "fine adjustments"
2) The 555 off time potentiometer was a 10K ohm 10-turn needs to be a 15K ohm 10-turn to get the 3% duty cycle for the other testing at a lower duty cycle ..... right now the lowest is about 22% at full resistance at 10K
3) The 12 volt diode at the positive rail unmarked is a 1N4007
These are the only changes that has been done and are much closer to the original October 2002 "Quantum" Article and when I have time I will issue a new revised schematic with these and any other changes needed.
From the looks of things you appear to be very very close to some excellent results with your load resistor ..... these items the 32mm resistor and the 10 ohm gate pot are very important items that appear to be the key to success for the results you want.
The PDF ..... what great work strange to have my name attached to such a document but you and any helpers you have are doing a stand up job giving the "open source" community the information at there fingertips to reproduce this circuit
Best,
Glen
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