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bypass cap calcualtion (Read 203 times)
Mostafa Elwakeel
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bypass cap calcualtion
Mar 19th, 2009, 5:05pm
 
Hello all ,

any one know how i can calculate bypass capacitors in low frequancy analog cirucit ??

thank you
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wave
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Re: bypass cap calcualtion
Reply #1 - Mar 19th, 2009, 6:06pm
 
I=C(dV/dT)
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Ken Kundert
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Re: bypass cap calcualtion
Reply #2 - Mar 19th, 2009, 7:07pm
 
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loose-electron
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Re: bypass cap calcualtion
Reply #3 - Mar 22nd, 2009, 5:01pm
 
Ken:

A pretty good writeup! I am presently dealing with a medical electronics problem and the original designer was totally clueless on anything above 10Khz - Its spaghetti inductors all over the place.

hope all is well
Jerry
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Jerry Twomey
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Ken Kundert
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Re: bypass cap calcualtion
Reply #4 - Mar 23rd, 2009, 9:22pm
 
Thanks Jerry.

Back in 1978 a very seasoned engineer at Tektronix by the name of Gene Cowan took me aside and explained the whole supply bypassing and decoupling story. Very simple if you understand what is going on, but rarely talked about in schools. Anyway, I though I would carry on his legacy by writing it up and putting in on the web. While I at HP I used one of their LCR meters to characterize the various components used for bypassing and decoupling, and ran into some weird, seemingly non-physical results, which eventually resulted in the papers on dielectric absorption, lossy inductors, and fracpoles. All in all, a rather interesting thread.

-Ken
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