Capacitor Dump Circuit - Negative Switching

[TxAggie00]

Hello All!

I have a question about negative switching for a capacitor dump circuit. Currently we are dumping a capacitor to 3 12VDC battery on the negative leg. We are using an SCR, 5.1V zener and two 3.2V LEDS. The capacitor is a 75V, 17,000 uF computer grade cap. The capacitor charges up to the battery voltage + the zener + the 2 LEDS (~48V - 50V) then dumps. We have some problems with the SCR "latching" and was told there was a better way using a FET. The problem is I am somewhat clueless on how that can be done. Anyone have any ideas?

Thanks,
Scott

Note: ignore the 33V zener in the attached picture. It is a 5.1V zener

 

[Averagesupernova]

An SCR is supposed to latch. I'm not sure what this circuit is supposed to be. The left hand side looks like a simple power supply with simple filtering but no regulation. Then the battery is hooked across the output with an SCR. Looks to me like as long as the power supply output voltage is less than 48 volts or so nothing will happen. But as soon as it approaches 48 volts the SCR goes into conduction and latches on (how it is supposed to) and a 36 volt battery is being charged with a 48 volt source. Kinda scary. So what is it you are trying to do?