What kind of on/off switch?

  • Thread starter Thread starter Dave Smith
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Dave Smith

I hope this isn't too silly a question.

I want to build a system in a box other than a standard computer case.
I think I have everything figured out but what kind of switch to use
for an on/off switch. Is it a standard switch, or something
different?

Thanks very much.
 
Dave Smith said:
I hope this isn't too silly a question.

I want to build a system in a box other than a standard computer case.
I think I have everything figured out but what kind of switch to use
for an on/off switch. Is it a standard switch, or something
different?
Click to expand...

Not a silly question and the answer is that the front panel switch on a case
is not really a switch - more of a button. It simply shorts 2 pins on the
motherboard to signal a power on / power off.

The PSU will have an on/off switch on the back. This is a 'normal' on/off
switch and will cut the power as you would expect. The switch on the front
of a case is a 'soft switch'. The area on the motherboard where all the LEDs
etc connect (the front panel connectors) has 2 pins which are connected to
the case switch. The motherboard has power whenever the PSU is switched on
and the front panel on/off switch simply sends a signal to the motherboard
to turn on or off.

You could actually turn the PC on and off by using a screw driver to short
the correct 2 pins on the front panel connector, but I wouldn't recommend it
as a solution!!
 
Not a silly question and the answer is that the front panel switch on a case
is not really a switch - more of a button. It simply shorts 2 pins on the
motherboard to signal a power on / power off.

The PSU will have an on/off switch on the back. This is a 'normal' on/off
switch and will cut the power as you would expect. The switch on the front
of a case is a 'soft switch'. The area on the motherboard where all the LEDs
etc connect (the front panel connectors) has 2 pins which are connected to
the case switch. The motherboard has power whenever the PSU is switched on
and the front panel on/off switch simply sends a signal to the motherboard
to turn on or off.

You could actually turn the PC on and off by using a screw driver to short
the correct 2 pins on the front panel connector, but I wouldn't recommend it
as a solution!!
Click to expand...
Ah HA!

Thank you very much for your explanation. I'll leave the screwdriver
in the toolbox and get a doorbell button or something ;-).
 
... REALLY a switch.

It is a momentary contact switch, that is an industry
standard term. There are myriad switches that are not just
a static "on/off" design, but that makes them no less
switches.

For the purposes of a computer, that momentary contact
switch is a -NO type, as-in Normally Open. Radio shack
carries a few but most look rather crude, maybe one that
looks like a small arcade button switch. The rest of theirs
aren't really suited for panel mounting rather than recessed
mounting because the plunger sticks up quite far past the
mounting flange.

here are a couple, the first link doesn't mention momentary
but I've used these before and they are momentary (either
that, or they used to stock one that looked exactly like it
that was momentary).
http://www.radioshack.com/product/index.jsp?productId=2062508

http://www.radioshack.com/product/index.jsp?productId=2062545

If one is willing to buy online, it would take a lifetime
or two to see them all and shipping can cost a half-dozen
times as much as the switch itself, but there are plenty of
fancy choices out there. MPJA has a pretty nice one on
sale this month though it's a bit large,
http://www.mpja.com/allpictspl.asp?p=16093+sw
Click to expand...
Yeah! I like that last one. Much nicer than an old screwdriver.

Thanks Kony
 
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