Is this power supply regulated?

Thread Starter

campeck

Joined Sep 5, 2009
194
I need 5v and 2.2A out of this plug in PSU. It's rated at 5v output and 3A.
Compaq
P/N 281855-001

I need it regulated but can't find out if this one is. I can't use a regulator IC because of the voltage drop and the only other PSU I have is 26V which will heat the *** up out of the IC.

Thanks.
 
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Jaguarjoe

Joined Apr 7, 2010
767
Measure the no load output. Should be 5.x volts, with no AC ripple. If its DC output is much higher than 5 volts its probably an unregulated supply.
Measure the output again, this time with a load on it-maybe a 5 ohm resistance for 1 amp load. Should be 5.x again (or real close to it) once again with no AC ripple.
Try bigger loads up to your 2.2 amps and look for similar results.
If the DC output sags as the load goes up and the AC ripple grows, its an unregulated supply.
 

marshallf3

Joined Jul 26, 2010
2,358
Exactly, those unregulated 5V wall supplies usually put out around 7.5V no load, even higher if they're lower amperage suppies as the secondary winding has a higher amount of internal resistance they depend on to drop the voltage.
 

Jaguarjoe

Joined Apr 7, 2010
767
In case yours isn't regulated, All Electronics has a 5 volt 3.75 amp switcher wall wart for only $4.75. That's pretty cheap.

Well, scratch that, they're out of them :(
 
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