DC wave form and Amps?

[dorf]

i have normal chinese cheap analog panel DC Amp-meter max.10A, how much does the voltage wave form affect a measurement result?
( i`m going to measure 12 car smart charger amps,among others )

 

[Harald Kapp]

Your question can't be answered in a simple way. The answer depends on how the instrument handles non-DC waveforms.

• A true RMS meter is good for a crest factor up to typically 4-5.
• A simple meter using rectifiers is not good for non-sinusoidal waveforms a all.
• A typical digital meter in DC range will integrate the measurand and depending on the waveform and frequency of the current the integration can nullify the superimposed AC component or show its full amplitude.

But: as charging a battery is equivalent to integrating the charge current over time, it is probably sufficient to use an integrating multimeter in DC range to read the charge current. Unless you use techniques like reflex charging that deliberately use negative current pulses to condition the battery.