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In the Forum: Melquiades Amplifier
In the Thread: 6 Channel Version of Super Melquiades
Post Subject: Too much currentPosted by hagtech on: 1/13/2008
Maybe if you didn't try to pull the caps down so fast.  Why the hurry?  Maybe a 500 ohm or 5k ohm resistor would be a more kind bleeder.  I think the peak current spike is not such a good thing for the capacitor.  You are also at the limit of the relay contacts.  There might be something in the relay specs that set a maximum for switching energy (V*I*t).  Six amps at 12 volts is easier on the contacts then 3 amps at 200 volts.  Perhaps there is an SOA curve, like for transistors?  I have not looked.

Also, at super high currents, the capacitors may not stay linear.  Sure they have ESR.  Maybe ESL limits the current in the electrolytics?  Maybe there is more to electrolytic chemical reactions we are not familiar with.  Basically, I think their risetime (to a current step) is slower than the film caps.  Maybe related to DA (dielectric absorption).  Multiple time contants in these devices.

How about using a MOSFET instead of a relay?

jh

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