Voltmeter question

[Neural Disorder]

I have a voltmeter that will measure up to 200 mA DC. Does this mean that it will have a problem giving me an accurate V DC reading if the power supply that I'm testing puts out more than 200 mA DC?

The reason I'm asking is that when I test various AC to DC power supplies that I have laying around, it always gives me a reading that is higher than it should be. For example, a 9vDC reads as over 15vDC and a 5vDC reads around 12vDC. Both of said power supplies are 500 mA DC. I don't have anything with less mA to test.

Thanks for your help!

[Prog]

Current reading has nothing to do with voltage reading.

It's impossible to tell with the info you give, but a capacitor on a power supply will charge to the peak voltage it sees. That might be why you read higher voltages.

Borrow a meter than can read higher current if you need to. Otherwise, just assume they can deliver as rated.

[Neural Disorder]

Thanks for the input.

I have tried two seperate meters, and both produced the same results. I just wanted to make sure that the higher mA wouldn't throw off the reading.

It's looking like it an issue with the two power supplies.

[Steverino]

I have a voltmeter that will measure up to 200 mA DC. Does this mean that it will have a problem giving me an accurate V DC reading if the power supply that I'm testing puts out more than 200 mA DC?


No. It just means that your particular meter will not measure more than 200mA in it's current measurement mode. If you were to try, it would more than likely blow an internal fuse.

The voltages you are reading are unloaded readings. If you were to check it's output with an appropriate load, you'd see a reading more in the neighborhood you were expecting.

:)

[Neural Disorder]

Ok, so if the power supply was plugged into somthing, then the reading would be closer to what is on the sticker?

I think I get it, thanks.

[Steverino]

Ok, so if the power supply was plugged into somthing, then the reading would be closer to what is on the sticker?

I think I get it, thanks.

You got it.

:)