next topic »

[Reply #15 on:]

In AC mode the average (to be precise the mean) voltage will be 0V for a repeating waveform, which means equal _areas_ above and below the 0V line.  The way AC mode is done is by connecting a capacitor between the scope probe and the scope's input circuit, which then averages at 0V due to the 1M load resistor to ground at the scope Y-amp's input.  In DC mode this capacitor is bypassed.