Hi fellow heretics, This setup is only interesting if the 12V battery is disconnected from the pulse generator. It is quite easy to feed a surprising amount of power through the high gate capacitance of a power mosfet and into the connected circuit. I have briefly fooled myself with this type of circuit. With a five volt pulse to the gate and a resonant circuit in the drain I found 20 volts present in the connected circuit even after removing the power supply connection. The mosfet gate input was effectively driving a resonant voltage multiplier in the drain circuit.
If the pulse input voltage has a strong influence on the measured output voltage it is a strong indication that this is what is going on. Replace the mosfet with a bipolar transistor and the effect should disappear. This could make a great project for the April issue of Nuts and Volts magazine. Without the explanation of course. George Holz Varitronics Systems [email protected]
