Computer power supply

M

Mountain Dwe

Guest
Can I use a OLD computers power supply box as a power supply unit for my
circuits?
I don't have a motherboard or anything for the power supply so id it
possible to jus hook up the power supply to the wall and use the 5V, 12V and
grounds?
 
hook up the power supply to the wall
and use the 5V, 12V and grounds?
Mountain Dwe
Click to expand...
Google is your friend.
http://groups-beta.google.com/groups?&q=group%3Asci.electronics.*+insubject%3Acomputer-power-supply+bench+OR+stand-alone+OR+experiments+OR+general-purpose
 
ok..
That sounds more trouble than convenience.. so let me ask this simple
question.....
Is the step down transformer in the power supply just a normal step down
transformer???
I mean can I salvage it and make my own general propose bench power supply?
I would assume I could use the rectifier diodes on the board too??

"JeffM" <jeffm_@email.com> wrote in message
news:1106693136.166004.164490@z14g2000cwz.googlegroups.com...
hook up the power supply to the wall
and use the 5V, 12V and grounds?
Mountain Dwe

Google is your friend.
http://groups-beta.google.com/groups?&q=group%3Asci.electronics.*+insubject%3Acomputer-power-supply+bench+OR+stand-alone+OR+experiments+OR+general-purpose
Click to expand...
 
"Mountain Dwe" <plasma@toi.ca> wrote in message
news:aaadneXThcAaQGvcRVn-1A@rogers.com...
ok..
That sounds more trouble than convenience.. so let me ask this simple
question.....
Is the step down transformer in the power supply just a normal step down
transformer???
I mean can I salvage it and make my own general propose bench power
supply?
I would assume I could use the rectifier diodes on the board too??

"JeffM" <jeffm_@email.com> wrote in message
news:1106693136.166004.164490@z14g2000cwz.googlegroups.com...
[just] hook up the power supply to the wall
and use the 5V, 12V and grounds?
Mountain Dwe

Google is your friend.

http://groups-beta.google.com/groups?&q=group%3Asci.electronics.*+insubject%3Acomputer-power-supply+bench+OR+stand-alone+OR+experiments+OR+general-purpose
Click to expand...
The stepdown transformer is a switched mode power supply
(switched primary, rectified secondary, usually pulse width modulated
circuit)

You *can* make a general 5V supply out of it, but beware of the "power good"
line
If using it, just use it "as is" since many of them are rather critical in
layout and used components
(especially if resonant-mode types)
I personally wouldn't dream of disassembling it to build another, I'd just
design another then
 
On Tue, 25 Jan 2005 20:17:05 -0700, Kitchen Man <nannerbac@yahoo.com>
wrote:

On Tue, 25 Jan 2005 17:08:31 -0500, "Mountain Dwe" <plasma@toi.ca
wrote:

Can I use a OLD computers power supply box as a power supply unit for my
circuits?

Absolutely.

I don't have a motherboard or anything for the power supply so id it
possible to jus hook up the power supply to the wall and use the 5V, 12V and
grounds?

As a minimum, buy some terminal boards and build yourself a proper
interface to the voltages, maybe mount everything on a spare piece of
wood. Understand the current and power limits of the supply. Fuse the
outputs appropriately, and realize that you will not have an indicator
of the status of the voltage and current without building your own
displays. You might want to integrate some switches for better control.
It all depends on the scope of what you want to do.
Click to expand...
Also ... I think all the computer supplies need some sort of load on
the 5V line to power up. A 6v automotive bulb will work.
 
Also, you may need to provide a load to the supply to keep it from shutting
down (protect mode). Many PC Supplies will not continue to run unless
properly loaded, either with a M/B or a "Dummy Load".
"peterken" <peter273@hotmail.com> wrote in message
news:DvBJd.5012$3N1.238688@phobos.telenet-ops.be...
"Mountain Dwe" <plasma@toi.ca> wrote in message
news:aaadneXThcAaQGvcRVn-1A@rogers.com...
ok..
That sounds more trouble than convenience.. so let me ask this simple
question.....
Is the step down transformer in the power supply just a normal step down
transformer???
I mean can I salvage it and make my own general propose bench power
supply?
I would assume I could use the rectifier diodes on the board too??

"JeffM" <jeffm_@email.com> wrote in message
news:1106693136.166004.164490@z14g2000cwz.googlegroups.com...
[just] hook up the power supply to the wall
and use the 5V, 12V and grounds?
Mountain Dwe

Google is your friend.

http://groups-beta.google.com/groups?&q=group%3Asci.electronics.*+insubject%3Acomputer-power-supply+bench+OR+stand-alone+OR+experiments+OR+general-purpose




The stepdown transformer is a switched mode power supply
(switched primary, rectified secondary, usually pulse width modulated
circuit)

You *can* make a general 5V supply out of it, but beware of the "power
good"
line
If using it, just use it "as is" since many of them are rather critical in
layout and used components
(especially if resonant-mode types)
I personally wouldn't dream of disassembling it to build another, I'd just
design another then
Click to expand...
 
On Tue, 25 Jan 2005 17:08:31 -0500, "Mountain Dwe" <plasma@toi.ca>
wrote:

Can I use a OLD computers power supply box as a power supply unit for my
circuits?
Click to expand...
Absolutely.

I don't have a motherboard or anything for the power supply so id it
possible to jus hook up the power supply to the wall and use the 5V, 12V and
grounds?
Click to expand...
As a minimum, buy some terminal boards and build yourself a proper
interface to the voltages, maybe mount everything on a spare piece of
wood. Understand the current and power limits of the supply. Fuse the
outputs appropriately, and realize that you will not have an indicator
of the status of the voltage and current without building your own
displays. You might want to integrate some switches for better control.
It all depends on the scope of what you want to do.

--
Al Brennan
 
Is it worth the trouble, how expensive are the power supplies your looking
at. If you are a novice, do you really want to be playing about with 240V
AC?


"Art" <plotsligt@comcast.net> wrote in message
news:j6WdnYsyhaztZmvcRVn-uA@comcast.com...
Also, you may need to provide a load to the supply to keep it from
shutting
down (protect mode). Many PC Supplies will not continue to run unless
properly loaded, either with a M/B or a "Dummy Load".
"peterken" <peter273@hotmail.com> wrote in message
news:DvBJd.5012$3N1.238688@phobos.telenet-ops.be...

"Mountain Dwe" <plasma@toi.ca> wrote in message
news:aaadneXThcAaQGvcRVn-1A@rogers.com...
ok..
That sounds more trouble than convenience.. so let me ask this simple
question.....
Is the step down transformer in the power supply just a normal step
down
transformer???
I mean can I salvage it and make my own general propose bench power
supply?
I would assume I could use the rectifier diodes on the board too??

"JeffM" <jeffm_@email.com> wrote in message
news:1106693136.166004.164490@z14g2000cwz.googlegroups.com...
[just] hook up the power supply to the wall
and use the 5V, 12V and grounds?
Mountain Dwe

Google is your friend.


http://groups-beta.google.com/groups?&q=group%3Asci.electronics.*+insubject%3Acomputer-power-supply+bench+OR+stand-alone+OR+experiments+OR+general-purpose




The stepdown transformer is a switched mode power supply
(switched primary, rectified secondary, usually pulse width modulated
circuit)

You *can* make a general 5V supply out of it, but beware of the "power
good"
line
If using it, just use it "as is" since many of them are rather critical
in
layout and used components
(especially if resonant-mode types)
I personally wouldn't dream of disassembling it to build another, I'd
just
design another then
Click to expand...
 
On Wed, 26 Jan 2005 12:44:39 -0800, JeB <no@spam.org> wrote:

On Tue, 25 Jan 2005 20:17:05 -0700, Kitchen Man <nannerbac@yahoo.com
wrote:

On Tue, 25 Jan 2005 17:08:31 -0500, "Mountain Dwe" <plasma@toi.ca
wrote:

Can I use a OLD computers power supply box as a power supply unit for my
circuits?

Absolutely.

I don't have a motherboard or anything for the power supply so id it
possible to jus hook up the power supply to the wall and use the 5V, 12V and
grounds?

As a minimum, buy some terminal boards and build yourself a proper
interface to the voltages, maybe mount everything on a spare piece of
wood. Understand the current and power limits of the supply. Fuse the
outputs appropriately, and realize that you will not have an indicator
of the status of the voltage and current without building your own
displays. You might want to integrate some switches for better control.
It all depends on the scope of what you want to do.

Also ... I think all the computer supplies need some sort of load on
the 5V line to power up. A 6v automotive bulb will work.
Click to expand...
Yeah, there's more to it than just plugging it in, I kinda overlooked
some of the finer details when I posted. But, where there's a will,
there's a way. It's a handy, pre-built switcher with common voltages
ready to go. 5V and 12V will let you build some interesting projects,
fun with op amps and low power auto stuff. Looks like there's plenty of
info on the web about how to get the thing running, and there must be a
gazillion of them laying around in junk piles.

--
Al Brennan
 
Kitchen Man (nannerbac@yahoo.com) writes:
On Wed, 26 Jan 2005 12:44:39 -0800, JeB <no@spam.org> wrote:

On Tue, 25 Jan 2005 20:17:05 -0700, Kitchen Man <nannerbac@yahoo.com
wrote:

On Tue, 25 Jan 2005 17:08:31 -0500, "Mountain Dwe" <plasma@toi.ca
wrote:

Can I use a OLD computers power supply box as a power supply unit for my
circuits?

Absolutely.

I don't have a motherboard or anything for the power supply so id it
possible to jus hook up the power supply to the wall and use the 5V, 12V and
grounds?

As a minimum, buy some terminal boards and build yourself a proper
interface to the voltages, maybe mount everything on a spare piece of
wood. Understand the current and power limits of the supply. Fuse the
outputs appropriately, and realize that you will not have an indicator
of the status of the voltage and current without building your own
displays. You might want to integrate some switches for better control.
It all depends on the scope of what you want to do.

Also ... I think all the computer supplies need some sort of load on
the 5V line to power up. A 6v automotive bulb will work.

Yeah, there's more to it than just plugging it in, I kinda overlooked
some of the finer details when I posted. But, where there's a will,
there's a way. It's a handy, pre-built switcher with common voltages
ready to go. 5V and 12V will let you build some interesting projects,
fun with op amps and low power auto stuff. Looks like there's plenty of
info on the web about how to get the thing running, and there must be a
gazillion of them laying around in junk piles.

But it's also tremendous overkill for a small bench supply. The fact
Click to expand...
that the supply likely needs a minimum mode should be a giveaway, you
will be wasting more current on the load than you use on the op-amps.

The only time such supplies are really useful is if you have a need for
high current.

They do make nice cases for small projects, though. You can pull out
the circuit board, strip some of the parts, and then build a linear power
supply inside. Grab a suitable transformer out of a junked consumer device,
use the bridge from the switching supply, get some electrolytics from
somewhere (since switching supplies work by generating a signal at a much
higher frequency than 60Hz, they don't need as much capacitance at the output
and thus they'll be too small for a 60Hz supply), and likely pull a 3terminal
regulator out of the same consumer device, or another.

Such a supply will not supply nearly as much current as the switching supply,
but you won't be wasting power on a load to keep the supply running, and it
won't be as noisy for those analog devices, and the regulation may be better.

Michael
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top