I know electronics testing with digital multimeters is easier than analog, but I'm wondering whether there is any electronic testing which can done with only "Analog" multimeters? For example measuring AC voltage with a square waveform: some people say it can't done with a digital multimeter because they are made for measuring sine waves from the grid. If that's right, are there any other tests that require analog multimeters?
Electronic – When we should use only an “Analog” multimeter
acanalogmultimeter
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Best Answer
You didn't ask for a complete exposition about the differences, so I'm not going to try and tabulate anything here. You asked about where an analog meter might be better (or should be preferred.)
Probably one of the better cases to try, if you are seriously looking to see where a very high quality digital meter (such as a Fluke 87) does far more poorly than a very cheap (nearly free, by comparison) analog voltmeter (such as a TekPower TP7040 -- an inexpensive, fine unit that includes the meter mirror strip [and in my opinion is better than the TekPower TP7050]), is to set up a signal generator to provide a sine wave at \$1\:\textrm{Hz}\$ that varies from about \$3\:\textrm{V}\$ to about \$7\:\textrm{V}\$ (in short, it has a DC bias to it that you ALSO want to see.) Now, hook up both meters.
A digital voltmeter (DVM) will spend all of its time rooting around, going from ERR to who knows what, trying to "auto-range." And, in effect, pretty much NEVER telling you anything useful at all except perhaps that the signal is "difficult." Meanwhile, the cheap analog voltmeter will very nicely swing back and forth between the two values and clearly show you a LOT better detail about what is taking place. You will even have a decent idea about the minimum and maximum values and that it moves smoothly between them.
It's like night and day.
Setting a DVM to manual mode and to the appropriate DC range (when both these features are available) stops the auto-ranging behavior and allows periodic display updates of the measurement. But the values appear to be taken "at random." It's much easier to see what is going on with the analog display, for some kinds of measurements. If also available in manual mode and also with the appropriate DC range selected, setting a DVM to use still faster display update rates improves this situation, too. (My Tektronix DMM916 allows this.) But the point remains for observing some situations. Besides, all we are doing here is narrowing cases by spending more money on the DVM.