The KA2803B is designed for use in earth leakage circuit interrupters, for stable operation of the AC line in breakers. The input of the differential amplifier is connected to the secondary coil of ZCT(Zero Current Transformer). The amplified output of differential amplifier is integrated at external capacitor to gain adequate time delay that is specified in KSC4613. The level comparator generates high level when earth leakage current is greater than the fixed level.