User talk:64.71.24.178

I have a question concerning this paragraph:

The peak-to-peak value is used, for example, when choosing rectifiers for power supplies, or when estimating the maximum voltage that insulation must withstand. Some common voltmeters are calibrated for RMS amplitude, but respond to the average value of a rectified waveform. Many digital voltmeters and all moving coil meters are in this category. The RMS calibration is only correct for a sine wave input since the ratio between peak, average and RMS values is dependent on waveform. If the wave shape being measured is greatly different from a sine wave, the relationship between RMS and average value changes. True RMS-responding meters were used in radio frequency measurements, where instruments measured the heating effect in a resistor to measure current. The advent of microprocessor controlled meters capable of calculating RMS by sampling the waveform has made true RMS measurement commonplace.

Why is peak to peak used in insulation ratings ? Pk-Pk implies an alternating waveform so insulation breakdown will occur at either/or polarity. Therefore the PEAK value would be more useful and common to express breakdown voltage.

There may be an error on the impulse (BIL) information. I thought it was 1.2uS to crest not 90% voltage as in a rise time (10% to 90%).

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