less hum: switching power supply?

[Jay Martin]

Before I continually get SLAMMED on this...I never said that the LM78xx
series were BAD, just that there are better alternatives.

Jay Martin

-----Original Message-----
From: Augusto Pinoche [mailto:augustopinoche at hotmail.com]
Sent: Monday, June 05, 2000 4:18 PM
To: synth-diy at node12b53.a2000.nl
Subject: RE: less hum: switching power supply?


Me to, i used a lot of LM78/89 devices
and have wery few problems ehit them.

The reverse factor becomes only a problem if
you have a large cap after the regulator and
no load, if you have a load the load will usually
discharge the cap.Infact the LM series needs a
small load if no load is present at the LM's
output they can start to oscillate.

Othervise i use LM317/227 and 2951 a lot and they
all work fine for ther apps when they are not overloaded.

DF


>From: Paul Perry <pfperry at melbpc.org.au>
>To: synth-diy at node12b53.a2000.nl
>Subject: RE: less hum: switching power supply?
>Date: Tue, 06 Jun 2000 02:37:58 +1000
>
>At 11:45 AM 5/06/00 -0400, Jay Martin  wrote:
> >I beg to differ,
> >The 78xx series of regulators do NOT have built in protection for 
>shorting,
> >overheating or reverse-voltage damage
>
>Hmm.. there is certainly overheating protection on the National Semi 78xxs.
>And, I've used a hell of a lot of them & never seen '8 volt spiking'.
>What do you have to do to get these spikes?
>
>perhaps this is time to note that not all chips with the same type #
>are always identical.
>
>paul perry Melbourne Australia
>

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