Pulsing high current into capacitive load?

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The discussion centers on pulsing 80 Amps at 1 KHz into a capacitive load of a few microfarads, which results in a high RC constant preventing the current from returning to zero between pulses. A temporary solution involved using a 0.75 ohm high current resistor in parallel, but this led to significant power wastage. The issue was ultimately resolved by generating a second low-powered pulse that is 180 degrees out of phase to discharge the capacitor effectively.

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waht
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I have to pulse 80 Amps @ 1 KHz into a capacitive load of a few uF. Unfortunately the RC constant is high enough that it prevents the next pulse to start from 0 amps. So in a sense the pulse generator delivers about 70 to 80 amps per cycle instead of 0 to 80 amps like it would in a non-capacitive load.

I fixed this temporarily by hooking up a 0.75 ohm high current resistor in parallel so it could discharge the load when the pulse is off. However I'm wasting a lot of power this way.

So I'm wondering if there is another solution?
 
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You might try being more specific about the purpose of your setup and what it is intended to accomplish.
 
put a higher resistor instead of a such small one.

your decay rate should be faster than 1msec, let's say it is about 0.2msec, so RC = 0.2msec => R = 200ohms?
 
Have you tried using a variable square wave generator and a mosfet?
 
Farlander said:
Have you tried using a variable square wave generator and a mosfet?

Thanks for replying, but the problem has been solved two months ago. We basically generated a second low powered 180 degree out of phase pulse to discharge the cap.
 
Most likely this can only be answered by an "old timer". I am making measurements on an uA709 op amp (metal can). I would like to calculate the frequency rolloff curves (I can measure them). I assume the compensation is via the miller effect. To do the calculations I would need to know the gain of the transistors and the effective resistance seen at the compensation terminals, not including the values I put there. Anyone know those values?

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