Article View: sci.electronics.basics
Article #33Re: power supply circuit
From: Phil Allison
Date: Mon, 09 Jun 2008 23:29
Date: Mon, 09 Jun 2008 23:29
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2368 bytes
"Don Klipstein" > One thing to watch for: RMS current being drawn from the transformer > exceeding the DC output current. The bigger the filter capacitor, the > worse this gets. ** That last claim is ABSOLUTE BULLSHIT !!!! Nothing new for this ignorant, septic asshole to make them. > Assuming that you will be using an adjustable voltage regulator, you > should be OK with a few volts of filter capacitor ripple, so don't make > the filter capacitors too big. ** Make it as big as you like and the rms ripple current will not increase. > As for a filter capacitor value: 4 volts ripple at 4 amps over the > approx. 6 milliseconds or so that the capacitor has to supply current > works out to 6,000 microfarads. I would not use more. Greater filter > capacitance makes the current waveform drawn from the transformer spikier, ** No it does not !! The whole idea is an idiotic MYTH put about by complete fools like Klipstein. > which makes the RMS current drawn from the transformer greater. I might > go for 4700 microfarads and only count on drawing 3-3.5 amps DC without > overheating the transformer. ** 20,000 uF would be a good value to use - cos increasing the filter capacitance above the minimum usable value has no effect on the rms current in the transformer windings. ...... Phil
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X-Google-Thread: 111d0a,5993850357c82189 X-Google-Thread: 112d1e,5993850357c82189 X-Google-Thread: 103407,5993850357c82189 X-Google-Attributes: gid111d0a,gid112d1e,gid103407,domainid0,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news1.google.com!news3.google.com!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail From: "Phil Allison" <philallison@tpg.com.au> Newsgroups: sci.electronics.basics,sci.electronics.design,aus.electronics Subject: Re: power supply circuit Date: Tue, 10 Jun 2008 09:29:06 +1000 Lines: 47 Message-ID: <6b5sltF3a3akbU1@mid.individual.net> References: <484d2532@dnews.tpgi.com.au> <slrng4r5gb.f46.don@manx.misty.com> X-Trace: individual.net yMISgBlr6oWM4whxG0D5YgEHPMeHiUQcC81ptW6d6AeijQG3Yg Cancel-Lock: sha1:FOji3xCr+wYpUWlCbzHt+OqRApg= X-Priority: 3 X-MSMail-Priority: Normal X-Newsreader: Microsoft Outlook Express 6.00.2900.3138 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3198 X-RFC2646: Format=Flowed; Original