The digital megohmmeter is composed of medium- and large-scale integrated circuits. This meter has high output power, high short-circuit current, and multiple output voltage levels (four voltage levels). Its working principle is as follows: the internal battery acts as a power source, generating a high-voltage DC through a DC/DC converter. This high voltage flows from the emitter (E) terminal, through the tested sample, to the drain (L) terminal, thus producing a current from E to L. After I/V conversion and division, the measured insulation resistance value is directly displayed on the LCD.
