How to measure phase angle on a scope?

To measure phase angle on a scope, connect the two inputs to the two sources, trigger off of one, and watch both. Measure the period of one and compare crossover difference with the other as a percentage of the period of the first, times 360 degrees.

Make sure the peak to peak offset for both inputs is equal, otherwise the crossover voltage won't be right.

Note that the period is 100% and is equivalent to 360 degrees. One way to make the calculation easier is to adjust the horizontal calibration so the first input has a period equal to 36 minor divisions - each division will equal 10 degrees in this case.

Also note, if you are comparing voltage and current, that your polarity is correct. This can be an issue if you are measuring across a small series resistor - the high side is voltage and the high to low side differential is current - but it is inverted.