The megger consists of two primary elements, both of which are provided with individual magnetic fields from a common permanent magnet, a hand driven DC generator and the instrument. In the illustration, coil A tends to move the pointer clock-wise and coil B anticlock-wise. Coil A is connected in series to R3 an unknown resistance whose value is to be measured. Coil B is connected to R2 and to the generator.
The registered trade name of a high-voltage, high-range ohmmeter. It has a built-in, hand-operated generator for providing the voltage needed to measure the electrical continuity, the insulation resistance, and the resistance between a component and an electrical ground.