Electronic components sources

From: melamy_at_earthlink.net <(melamy_at_earthlink.net)>
Date: Wed Mar 24 19:13:10 2004

actually, the usual switches these days on PC computers are only
logic switches back to the power supply. The power supply does
"tap into" the ac line to get a little power it needs.

My P4 that I built last year uses an ANTEC case and there is
no AC going out to a front panel switch - it is only a push button.

A good rule of thumb is that if a switch clicks then it probably
has AC on it. If it doesn't then it MIGHT be only low voltage.
As an electrical engineer, I would not take the chance and assume
it is low voltage without checking.

Any computer that is pre-ATX will have AC voltage on the power
switch. Some early ATX and maybe even now (I don't know for sure)
may still have a real switch out front.

The older mini-tower systems that have a power switch out front
usually had a AC connector on the back of the power supply and
a four conductor cable that ran out to the power switch. The
power could tap into the AC line without affecting the switch
out front.

The older NEC, etc systems sometimes had a seperate power suply
with an AC connector and cables, etc that were not integrated
into the power supply like the PC, AT, ATX supplies that came
along.

best regards, Steve Thatcher

>--- Original Message ---
>From: meltie <lists_at_microvax.org>
>To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk_at_classiccmp.org>
>Date: 3/24/04 7:23:31 PM
>
On Wednesday 24 March 2004 23:45, William Donzelli wrote:
>> > Assuming the switch functions correctly (and is wired correctly),
>> > the behaviour of a device with such a switch in the off
position
>> > is pretty certain: it's identical to a device that has the
>> > mains lead pulled out.
>>
>> Not completely. The cord, all the way to the switch, is still
energized.
>> And remember, many of today's devices are not always completely
off -
>> they might tap into the line just a little bit (clock, for
instance).
>
>How is this different from a circuit that doesn't chop both
conductors?
>
>alex/melt
>
Received on Wed Mar 24 2004 - 19:13:10 GMT