[sdiy] Power Supply Design Questions

[Scott Gravenhorst]

That's really nice.  Thanks.

patchell <patchell at silcom.com> wrote:
>If you go here:
>
>    http://www.silcom.com/~patchell/powersupply/powersupply.html
>
>    You will find a scan of something I wrote up on how to select a
>filter capacitor for a three terminal type regulator.  I generally allow
>for 3 volts drop, sort of a margin of saftety.  You have to remember
>that there will be supply ripple going into the regulator, and you need
>to make sure that the voltage never goes below that magic point.  So, it
>is not so much the transformer you have to select, but rather, the
>filter capacitor.
>
>Scott Gravenhorst wrote:
>
>> Some questions I have:
>>
>> At what input voltage should a LM78xx or LM79xx type
>> regulator be run for minimum heat?
>>
>> I read in data sheets that 2 volts is the usual value for
>> dropout voltage (at 1A).
>>
>> Would this be the point (well, somewhat above it) at which
>> the regulator would heat up the least?
>>
>> Operated so, does this also mean using a transformer with
>> better current capabilities?
>>
>> Thanks all.
>>
>> =========================================================
>> - A smoking gun is one that's already been fired.
>> - That which gets rewarded, gets done.
>> - What good are laws that only lawyers understand?
>> - Government: The other religion.
>> - The media's credibility should always be questioned.
>>
>> -- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
>> -- Linux Rex         | RedWebMail by RedStarWare
>> -- FatMan: home1.gte.net/res0658s/FatMan/
>> -- NonFatMan: home1.gte.net/res0658s/electronics/
>
>--
> -Jim
>------------------------------------------------
>* Visit:http://www.silcom.com/~patchell/
>*-----------------------------------------------
>* Come to the Pacific Southwest DIY Meet
>* April 12, 2003 10am-5pm
>* Santa Barbara, CA
>* http://www.silcom.com/~patchell/synthdiymeet.html
>* for details
>*-----------------------------------------------
>
>

=========================================================  
- A smoking gun is one that's already been fired.
- That which gets rewarded, gets done.
- What good are laws that only lawyers understand?
- Government: The other religion.
- The media's credibility should always be questioned.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.gte.net/res0658s/FatMan/
-- NonFatMan: home1.gte.net/res0658s/electronics/