Understanding analog voltmeter calibration

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The discussion focuses on the calibration and wiring of a Zantum Class 0.5 analog voltmeter, where initial confusion arose over calibration screws mistakenly thought to be wiring terminals. Users clarified that the blue screws are the actual calibration trimpots, while the green terminal block screws are for connecting sensing wires to the battery. A significant issue was identified regarding static electricity affecting the meter's needle, which was resolved by ensuring the meter was not placed on static-prone surfaces. The conversation also touched on the importance of proper calibration methods and the internal components of the voltmeter, highlighting the precision of its trimpots. Overall, the thread emphasizes the need for careful handling and understanding of the voltmeter's calibration to avoid misinterpretation of readings.
  • #31
Upside of 'Analog' is you may see needle twitch. No substitute for well-handled 'scope, but often a ''Huh ??'

Analogue or digital, you must be aware of wave-form, ripple etc etc and how instrumentation responds..

Sadly, this is a big problem with wannabe 'Over Unity' inventors: They embrace inappropriate readings...
FWIW, I was banned from a fun hobbyist electronics site for suggesting their resident 'Over-U' guru dispense with his wondrous array of mismatched instruments and simply attach a festoon of incandescent lights.
Given he was site's major sponsor, I was 'run out of town'...
 
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  • #32
For service work, I use moving coil multimeters in preference to a digital multimeter.

With a DMM, the position of the decimal point is most critical, but is the least visible. Intermittent faults are very hard to find with a DMM. Servicing PWM systems with a DMM is fraught with sampling problems.

For 12V and 24V motor vehicle service, where there are connectors, moisture, dirt, salt, and vibration, a test lamp with a filament will be more honest and produce quicker results, than a high resistance DMM.

A DMM is only needed for setting up power supplies and calibrating instruments.
They are now so much cheaper than a moving coil meter, that DMMs are ubiquitous, and so will lead many beginners into trouble, wasting a lot of time.
 
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  • #33
Baluncore said:
For service work, I use moving coil multimeters in preference to a digital multimeter.

My last couple Fluke DMMs at my last couple EE jobs had bargraph LCD displays in addition to their numeric displays. I usually found them to respond quickly enough to satisfy my need to see quickly changing numbers (well below oscilloscope needs). Have you used any DMM bargraphs like those?
 
  • #34
berkeman said:
Have you used any DMM bargraphs like those?
Yes, but the lower-cost non-fluke meters have slower bar-graphs, while unattended Fluke meters tend to go missing.

Bar-graphs also do silly things while range-switching induced by on-off intermittent signals. There are workarounds, but I am more interested in solving the problem than solving the test instruments.

It's horses for courses, I have low-cost versions of both types of meter at each workbench, and in each vehicle toolbox.

Everything is a compromise. If I need precision, I will use a reference grade meter, but it will not remain lying around, or being shaken in a vehicle.

I do appreciate the John Fluke Manufacturing company differential voltmeters, but I originally learned to read an AVO-8, so I guess moving coils are just an extension of my personality.
 

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