crackling was always a lot more prevalent with a monofilar, one wire being driven by 2 fets connected together, something else I did with the bifilar coil experiments which seemed to increase the crackling was to use moving coil meters at the supply end, the other thing I did was to have all earth wire from everywhere the same length and star connected back to the supplies.
The process for tuning for crackles was to start with the coil voltage low, sweeping the phase from 0-255nS and gradually increase the supply voltage to the fets, once the crackles start fet death is not far away, if i remember correctly the voltage was between 30V and 50V.
Do try to work with the bifilar first as the monofilar is very unstable and fet death is always not far away.
Sometimes the crackles can be there and not heard by the ear but a small capacitive michrophone will pick them up, i was recording my videos using a PC with a cheap microphone plugged into the mic port and placed near the coils. The other way is with a magnet placed near to the coils, you feel the crackling as violent physical pulling of the magnet.
PS The last experiment i did and did not record properly which i should have really was to look to see if i could generate the big pulse by passively delaying the pulses. I used 1 fet channel which was switching on and off for about 50nS, i then divided the current path into 2 wires and added fast diodes in one path to delay the pulses, if i remember correctly i then drove 2 coils (bifilar) with each current path, and after much time on the bench did manage to create the big pulse seen in my videos.
Question
Do you see the big pulse appearing when you sweep, because you should at least be seeing that even if the crackles are not there.
|