Useing AT switcher as bench supply.

You do realize that switching psu tend to explode if they are left without loads on the outputs, right?

- Tim -

Behold, Tim signalled from keyed 4-1000A filament:

Eh?

I've been using an XT switcher for a 12V/5V bench supply for years :-/

While theoretically true, almost all PC power supplies will not "explode", and to say so is fear mongering, at best.

Most PC power supplies will simply shut down (or not start up). Some better supplies have internal loading so that no external load is required.

I usually plug > You do realize that switching psu tend to explode if they are left without

Damn, you told him! We wanted to see if we could get an Ottawan winning the Darwin Awards ;)

the 12

molex

where

I will google this one out. AT switchers need a load connected to them ATX switchers will switch on when there when a load is detected. I think is to prevent output caps from bursting.

I will use a old poor quailty ATX switcher with a SPST switch a 1K resistor and a green LED to ground for power on. I also Modded that one with molex connectors. I put the extra wires out for that.

where

AFAIK Power good on an AT supply is an output to tell the Mboard that the power supply is stable, not an input. If you have no output it is because there is no load probably.

You need to google.

I've seen electrolytic caps explode when subjected to overvoltage.

But power supplies for PCs, for as long as I can remember, have had overvoltage shutdown that prevents them from doing anything except shut down.

I have the scars to prove it. Some switching psu will take off with no load, and the freq will exceed spec and bang! they go ballistic.

Been there, done that.

A common switcher CAN do this, but a CSA approved, or UL approved in the US of A computer power supply MUST protect itself from this. They all have overvoltage and over current shut-down.. One thing that makes them kinda nice for bench supplies.

"explode",

required.

TTYL

without

out

use

one

banana

switcher

I've seen 12V equipment lift off the bench when connected to a 28VDC power supply; so yeah, those electrolytic caps can be quite destructive when they let go. I've also seen the insides of equipment afterwards, where the shreds of the 'lytic are stuck all over the rest of the components on the PC board. So I can relate to the shrapnel that you've experienced. But all the PSes that I've seen have a crowbar OVP circuit that just shorts the output to ground with a SCR when the overvoltage is encountered.

Or (just to add another to the list of possibilities) it just won't regulate accurately. That could also affect regulation of the 12V output.