Analyze the ripple test circuits for high voltage output of special power supply

Based on the definition of ripple of switch power supply, combined with the causes of switching power supply and use of oscilloscope on switching power supply output ripple or noise detection, analysis and comparison of the four feasible test circuit. Power source for testing is 220V 50Hz input and -1200V dc voltage output, the voltage of power source output is mainly contains the second harmonic of the working frequency and switching frequency with the frequency of high frequency ripple, switching noise and random noise.