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[AMPS] resistors

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Subject: [AMPS] resistors
From: (Eric Wicklund)
Date: Wed, 24 Feb 1999 20:43:32 -0800

>>>>>>Ä  What mechanism recharges the capacitor?
>>>>>An incomplete discharge. Something very easy to do for an inexperienced
>>>>?  Bzzzzzt.  You said recharge.
>>>The mechanisms causing apparent recharge were discussed in good detail
>>>by Bob Pease of NatSemi in Electronics magazine (I think) a few months
>>>ago. I'll post a reference when I find it.
The mechanism that causes this is dielectric absorption.  The model for a
real capacitor
includes many series resistors and capacitors that are then in parallel with
the primary capacitor
value.  When you short out a capacator, it takes a while (depending on the
type of capacitor) to
discharge all of the stored charge.  This is why you can short out a
capacitor several times before
the charge is depleted.  To see this, charge up an electrolytic cap and then
short across its terminals....wait a few seconds and do it again.  You
should see a spark.   I'm not sure how much
of this you would see with a good oil filled cap though.
Eric KR7A

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