Re: Choosing Cap Size in Power Supply

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Article #17869

#17869

From: Kevin G. Heppell
Date: Mon, 27 Jul 1987 04:41

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In article <5705@ut-ngp.UUCP> jjr@ngp.UUCP (Jeff Rodriguez) writes:
>
>I'm building a general-purpose power supply...
>
>How do I choose the size of capacitor to place across 
>the output of the rectifier?  I once heard that the 
>rule-of-thumb is 1000 micro-F per 1 A of current.  
>Is that reasonable?

In one of TI's applications manuals they list a graphical solution:

O.H. Schade, "Analysis of Rectifier Operation", Proc. IRE.,
   Vol. 31, 343, 1943

Basically, the desired filter (capacitor plus shunt resistance
of the regulator) depends on several factors, including whether
you use a full or half wave rectifier, line frequency (usu. a
constant, but who knows :-), peak input (transformer voltage),
and desired output voltage.  I'm sorry, but I haven't worked with
the method enough to give you a specific answer.

The TI manual "Linear and Interface Circuits Applications",
  Volume 1, 1985 gives a good, _general_ discussion of basic
  linear regulators, their own parts notwithstanding.

Disclaimer: I have no connection with TI except someone gave
me a bunch of their books for free.

--------------------------------------------------------------------------------
    Kevin G. Heppell                    USNail: 784 Santa Barbara Rd.
    USENET: ucbvax!cory!heppell                 Berkeley, CA  94707-2046
    arpa:   heppell@cory.Berkeley.EDU           (415) 528-6396

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From: heppell@cory.Berkeley.EDU (Kevin G. Heppell)
Newsgroups: sci.electronics
Subject: Re: Choosing Cap Size in Power Supply
Message-ID: <3109@zen.berkeley.edu>
Date: Mon, 27-Jul-87 00:41:16 EDT
Article-I.D.: zen.3109
Posted: Mon Jul 27 00:41:16 1987
Date-Received: Tue, 28-Jul-87 00:36:38 EDT
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Keywords: bridge filter

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