this is a follow up from https://superuser.com/a/958165/43268

It was suggested that i check a 19VDC power supply for "dirty" voltage. If i had a oscilloscope i could probably follow the excellently documented steps from http://www.righto.com/2012/10/a-dozen-usb-chargers-in-lab-apple-is.html

but all i have is a multimeter. it is a decent one. a fluke 87V. It does not have data logging but does have a "fast mode" that works on a little bar graph and it has hold max/min.

is it possible to check the power supply with just that? would a dirty power supply show up how if all i can measure is the output voltage while under load? would the voltage fluctuate? how much fluctuation should i watch out for?

  • \$\begingroup\$ changed to an answer. \$\endgroup\$ – BenG Aug 17 '15 at 23:22

Set your DMM to AC voltage and measure the output. It will ignore the DC values similar to AC Coupling mode on oscilloscope.


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