Re: Question regarding AC/DC converter ouput

Ralph Mowery uttered with a toothy grin in sci.electronics.repair:

"Jed" <jed@xxxxxxxxxxxx> wrote in message
news:Xns97E01ADCE792CXns96DB93B27837je***@xxxxxxxxxxxxxxxxxx
Hello All!

I recently was looking at a power converter as a possible problem with
a flatpanel monitor.

When I placed a VOM on a 12VDC ac/dc power converter I measured 14 or
better
volts. I was hoping someone in here could tell me if this is normal,
....
Depends on the device. If it is a big supply rated at several amps or
more and is to run equipment usually ran in a car the voltage is
normally set at 13.8 volts. This is the "standard" voltage of a car
charging system with the motor running.

If it is a wall cube, they are not usually regulated. The volage will
be somewhat higher than 12 volts and drop under load to near 12 volts.
If the supply just has a rectifier and capacitor in it and is unloaded
it will be the roughly 12 volts times about 1.4 (peak part of a 12 volt
ac rms reading). Think that 1.4 is close for the multiplier. This is
because the capacitor will charge near the peak voltage of the sine
wave.




Thak you!
.

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