Subject: Re: V regulator input cap size?
Date: Tue, 22 Oct 2002 18:29:13 +0800
References: <0001HW.B9D991AD000C5917163F7590@news.covad.net> <email@example.com> <0001HW.B9D9CD54001A5D15163F7590@news.covad.net> <3DB48CD0.447092BF@rica.net> <0001HW.B9DA3AFA00342030163F7590@news.covad.net> <4y97qUAX7Qt9EwBY@jmwa.demon.co.uk>
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On Tue, 22 Oct 2002 09:39:51 +0100, John Woodgate
>I read in sci.electronics.design that DaveC wrote (in
><0001HW.B9DA3AFA00342030163F7590@news.covad.net>) about 'V regulator
>input cap size?', on Mon, 21 Oct 2002:
>>How about a simple voltage divider across the 35vac liine? Say, divide such
>>that one of the resistors has 20 volts across it. It won't be the example of
>>efficient use of energy, but the circuit doesn't use more than about 300mA at
>>Is this a do-able solution?
>Well, sort of, but you get lots of heat. Is the 300 mA constant? If so,
>you can simply put a resistor in series with the bridge rectifier, on
>the AC side. This also changes the operation of the rectifier to more
>nearly a current-fed type. You would need to drop 20 V at around 500 mA,
>which is 40 ohms, 10 W. Not elegant, but possible.
If it's a constant current why not use a suitable 24volt automotive
globe? - gives you a visual indication of On/Off as well!
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