11-22-2023, 09:42 AM
I have been working on this and have held off posting until results were validated and I could explain things. The problem with the old circuit was it would blow the 18A mosfet. By the time partzman at OUR determined this was caused by an 80 amp inrush current, I was out of those mosfets. No big deal as I needed higher amp ones anyway.
I have rebuilt the entire circuit from scratch with all new components and the results are consistent. There is no gain. The best cop is 0.6813. What the heck! I ran the first tests 10 times with consistent results! Now I feel like a fool. Well, read on…
It took a long time to piece together what happened. I was fooled by a faulty on/off switch and the normal behavior of the little PPK signal generator. The original schematic is attached for reference.
The test procedure was close S1 to charge C1. Open S1 and close S2. When S2 is closed it also turns on the PPK module. Push the button on the PPK to pulse. Open S2. Opening S2 turns everything off and isolates C1. Unplug the trafo. Measure the voltages. Simple. What could go wrong.
What happened is the faulty S1 did not fully open so the trafo was still providing some charge to the circuit. Also, what I didn’t know then is when a PPK is first turned on, it emits a single output. That single unobserved output closed the mosfet and it shorted out to a closed condition between the source and drain, every time.
So the instant S2 was closed, before I pulsed the circuit, C2 began charging while C1 was still being fed by the trafo. This gave the false expenditure from C1 and the false gain in C2.
A bad mechanical switch along with an unexpected pulse is all it took. Another hard lesson learned.
My apologies to everyone.
I have rebuilt the entire circuit from scratch with all new components and the results are consistent. There is no gain. The best cop is 0.6813. What the heck! I ran the first tests 10 times with consistent results! Now I feel like a fool. Well, read on…
It took a long time to piece together what happened. I was fooled by a faulty on/off switch and the normal behavior of the little PPK signal generator. The original schematic is attached for reference.
The test procedure was close S1 to charge C1. Open S1 and close S2. When S2 is closed it also turns on the PPK module. Push the button on the PPK to pulse. Open S2. Opening S2 turns everything off and isolates C1. Unplug the trafo. Measure the voltages. Simple. What could go wrong.
What happened is the faulty S1 did not fully open so the trafo was still providing some charge to the circuit. Also, what I didn’t know then is when a PPK is first turned on, it emits a single output. That single unobserved output closed the mosfet and it shorted out to a closed condition between the source and drain, every time.
So the instant S2 was closed, before I pulsed the circuit, C2 began charging while C1 was still being fed by the trafo. This gave the false expenditure from C1 and the false gain in C2.
A bad mechanical switch along with an unexpected pulse is all it took. Another hard lesson learned.
My apologies to everyone.
