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Wall Transformer Gone Bad?

I have a 120v AC Class 2 Power Supply that is rated 12v 500mA DC output. On the voltmeter, its output is ~20.4 volts. What typically goes bad that causes such a high spike in the output voltage?

Reply to
VHarris
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I don't have a 24 ohm load, but I connected a 150 ohm load and the voltage across the leads dropped to 17.3 volts.

Reply to
VHarris 

--
Lern 2 spel.
Reply to
John Fields

Right.

So the wallwart is fine.

Graham

Reply to
Pooh Bear

How does the AC power supply have a DC current rating? You mean it is

120VAC input with 12VDC @ 500mA output. This power supply is unregulated, it's only function is line step-down, rectification, and some filtering. The output DC voltage will be a function of loading, settling to 12VDC with 500mA of current draw. If you need 12VDC at lesser current, you will have to add an external regulator, or buy one that has the word "regulated" on the label.
Reply to
Fred Bloggs

"VHarris"

** Connect a 24 ohm ( 6 watt rated ) load.

See what happens.

............ Phil

Reply to
Phil Allison

** Learn how to post.

The learn ohm's law.

......... Phil

Reply to
Phil Allison

Or put an extra load resistor in parallel with the load you want to run, that will bring the voltage down.

Reply to
kell

"John Fields"

** Yawn.

** A nice cover story.

........ Phil

Reply to
Phil Allison

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