Discharging circuit problems

Thread Starter

lomaikai

Joined Sep 8, 2011
6
I have been working on a circuit (similar to car ionizer circuit), which is able to charged up a capacitor to voltage as high as 1.8kV. I have a diode which is able to block reverse voltage up to 2kV interfaced between the charging circuit and the discharged capacitor.

This capacitor is then connected to two electrodes (air gap) that discharge when the breakdown voltage is reached.

The problem is, whenever the capacitor discharges, a random component in my circuit will be spoilt. What must i do to overcome this problem?
 

crutschow

Joined Mar 14, 2008
25,395
The problem is likely the high current pulse through your ground, which is generating ground voltages high enough to zap components. Since the output is provided by a transformer I suggest isolating the output ground from your driver circuit ground. That will minimize any discharge currents flowing through the driver circuit.
 

Thread Starter

lomaikai

Joined Sep 8, 2011
6
hi crutschow, thanks for the suggestion! Regarding the Isolation, does it means i have to place the output ground to the ground of another DC supply or there are other ways to do the isolation within the circuit itself. Thanks !
 

crutschow

Joined Mar 14, 2008
25,395
hi crutschow, thanks for the suggestion! Regarding the Isolation, does it means i have to place the output ground to the ground of another DC supply or there are other ways to do the isolation within the circuit itself. Thanks !
The output common does not necessarily need to be connected anywhere. If you want to keep it from floating and developing a static charge just connect a resistor (say 100k-1meg Ω) between the output common and your circuit ground. That will tie the two commons together to keep them at the same potential but minimize any current flowing between them during the discharge.
 
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