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Just received this meter after buying online - RMS reads ok, peak reading position buries the needs all the way to the left - looks out of alignment. Anyone have ideas?

How to align peak reading

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Most meters have a calibration adjustment or two internally.

However- some meters- especially the old VTVMs used a 1meg resistor in the AC test probe. and they had a seperate DC and AC terminals and test leads because of it.

If it were mine, I would open it up and look for non factory modifications. I would suspect a 1 Meg resistor is missing or shorted somewhere in the Peak section. it may be some other value but should be proportional.to what is present the RMS section.

Posted on Feb 14, 2012

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The rms and average values of an MSW depend on its duty cycle D, the fraction of a cycle for which the signal is not at zero. In a well-designed inverter, the duty cycle will be adjusted when the DC input voltage goes up and down to maintain the nominal rms output voltage. If we use peak voltage Vp to mean the magnitude of the positive and negative voltages the signal goes to, then Vavg for an MSW is equal to Vp times D, and Vrms is equal to Vp times the square root of D.

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