Thanks. My daily driver bench meter is a Siglent 4065A; I could probably configure it to pick it up - but it almost becomes a catch 22 of not knowing what to configure it to unless you know what the anomaly is (or knowledge of it even being there are all) - so in the end, a "visual explorer" like a scope is far more the right tool for the job (for me) than the DMM as I really don't need 6 1/2 digit resolution of a PSU rail - but I do need the easiest possible visualisation of what's happening.
Well, but if you just want to measure DC, you wouldn't use an oscilloscope for that.
DC&AC mode is exactly for situations where you don't expect an AC component, but it shows up anyway.
Then you can use the scope to see what's going on.
I don’t have a Siglent 4065A, but on the ZT-225, it’s just one setting on the switch.
You don’t have to configure anything.
Like I said, you can do that only if you are measuring a battery, outside device. Otherwise, you don't know if there is only DC there.
Funny enough you can have ripple on the battery too, if connected and you are loading it with pulse load/switcher or charging with switcher or some kind of pulse charger (they exist). Extensive ripple in that case would point to large internal resistance of the battery, which could point to bad/ decreased capacity/empty battery.
Best is to go the other way around. You probe everything with scope (provide you are working on low voltage device that doesn't hide 5000V in weird places) and that is usually good enough for go/no-go test. I used 3.5 digit meter many times to check status of SLA batteries and if they charge. If you want to balance Li-ion cells in a pack to millivolts, then break out decent multimeter for additional decimal places.
Although SDS800xHD will do that well enough too, because it will still show millivolts on 3,7V cell, and since you are balancing (comparing) cells, that is relative measurement that is not dependent on DC absolute accuracy specification 0.5%.
Multimeter is on my desk all the time because of other stuff, diodes, continuity, etc. mostly. Voltage measurement with multimeter comes when we already know what are we measuring and want more detail or accuracy.
For instance, I just repaired old external rack mount Soundcraft PSU for a big sound console. It has several voltage buses. All of them checked by scope first, found problem with the scope, used meter to check connections, tweezers for resistance of some suspicious resistors, and checked few diodes. Then repaired it and finally checked ripple with scope and used multimeter to set exact voltages.
That final step was not needed whatsoever, that was simply my OCD of "doing things right".
So apart from last step (that was not needed, scope voltage measurement would have been better than PSU spec) I used scope and resistance, continuity and diode test on meter and tweezer.
As for measuring ripple with meter, unless you are measuring 50 Hz ripple, you will not see much on simple multimeters. And even then, limited bandwidth might cause lots of error. Scope is exactly the tool for that. From 50 Hz to multi MHz switchers ripple.
With signal shape on the screen, 6 measurements at the same time, histograms and FFT. It is really fast and gives so much information at the same time. You touch the probe to test point and you go "Aha!" and move on until you get to problem.
And it is universal principle both for devices you know well (where you exactly know what you expect to see on what point) and for something you never saw before, where you need to reverse engineer how it works.
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