Re: Dual Power Supply


Pooh Bear wrote:
> Chris wrote:
>
> > think at least 20,000uF
>
> 20,000uF for 2 amps !
>
> Good Lord.
>
> Graham

Yup. You want the rails to be about +/-20V for a +/-15V supply. If
you use 16VAC transformers for the + and - power supplies , I'd guess
you'd have a peak voltage after rectification of 21V or so. A really
large cap (22,000uF) means there's less than a volt of ripple.

Big linear power supplies generate a lot of heat. A big cap is cheaper
than a bigger heat sink.

But I guess I was talking more about a variable tracking supply -- I
guess I got a little off track. If the OP chooses a design that
doesn't have overtemp shutdown (like the 723 designs in the data
***), he may be in a situation with a shorted output where the pass
element is cranking as much as 40 watts.

Thanks for the spot. Glad somebody's checking -- we couldn't have
incorrect information floating around the internets. If that happened,
it would be just like TV journamalism. ;-)

Chris

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