Simple DIY DVM Voltage Reference

[ppppenguin]

Terry, as you have suggested, explaining the difference between accuracy and precision isn't easy. Nor are the concepts of adequate precision and accuracy. Then add the effects of loading by the meter. Experienced folk like you, me and Mark will normally get it right without thinking but it can be a struggle for a novice.

At a more advanced level, using a scope probe can give various problems. My favourite trick for checking if the probe is affecting the circuit is to touch a 2nd probe on to the same point. If the waveform changes significantly then probe loading is affecting the measurement.