What is Common Mode Rejection Ratio (CMRR) and how to measure it on a high voltage differential probe or differential amplifier. Youtube: Extended 30min version: https://www.youtube.com/watch?v=4gi2B3LrCww Differential Probe How It Works: https://www.youtube.com/watch?v=GOlgaEK2Hsk High Voltage Probe reverse engineering: https://www.youtube.com/watch?v=GOk1BYKSsOI&t=2s Forum: https://www.eevblog.com/forum/blog/eevblog-1521-how-to-measure-differential-probe-cmrr/