Have a handheld DMM measure pretty well an oscillating DC

[abdulbadii]

How can our handheld DMMs pretty well measure an oscillating DC current?

 

[danadak]

Depends on meter, and of course the oscillation waveform it is measuring. Oscillating DC is
AC. Waveshape is an issue. Thats why some meters are true RMS for non sinus waveforms.
Some can measure peak. Meters that are not true RMS have waveshape factor correction
limitations.

So consult meter manual as to its capabilities.

True RMS AC Measurements

Test & Measurement

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What is true-RMS? | Fluke

The need for true-RMS meters has grown as the possibility of non-sinusoidal waves in circuits has greatly increased in recent years. Some examples include variable speed motor drives, electronic ballasts, computers, HVAC, and solid-state environments.

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Regards, Dana.

 

[crutschow]

What is the frequency of this "oscillating DC"?
Most multimeters have a fairly low frequency AC response limit.

 

[unclejed613]

this is territory where an oscope is more useful than a DMM. about all you can tell using a DMM is whether it's AC with a DC offset (the signal crosses the zero line because the amplitude of the AC component is larger than the magnitude of the DC component) or DC with an ac signal riding on it (the waveform doesn't cross the zero line because the AC amplitude is smaller than the DC magnitude). beyond that most DMMs are pretty useless, because frequency and waveshape of the AC component remain unknown.