Using the resistance of the discharge process, resistive load will seriously heat, please pay attention to safety.Please install the 50W aluminum resistance (has been soldered half part of high temperature line) to a metal plate to use.This circuit voltage in order to improve the measurement accuracy, specially designed DC bias, when the terminal connects nothing will display a small voltage, but does not affect the actual measurement, if you are shorting the input terminal (absolute 0V) will display 0. If you want to know the principle, you can check the superposition theorem of electrical engineering.
