[AMPS] resistors

[ericw@accessone.com (Eric Wicklund)]

>>>>>>Ä  What mechanism recharges the capacitor?
>>>>>
>>>>>
>>>>>An incomplete discharge. Something very easy to do for an inexperienced
>>>>>person..
>>>>>
>>>>?  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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