555 simple electric leakage protector circuit

Published:2011/6/10 22:02:00 Author:nelly | Keyword: electric leakage, protector | From:SeekIC

As shown in the figure 10-7, the protector is composed of transformer, preamplifier stage and monostable delay circuit and relay. The protection action current is lower than 3mA, the action time is lower than 0.1s. The transformer HL adopts high conductive magnetic ring, primary fire line and zero line parallel winding 5 turns, secondary polarity winding 500 turns. In normal times, HL's primary line current is in balanced state, secondary polarity does not output signal. When it comes load electric leakage, secondary polarity has signal current, after amplified by VT1, 555's 2 foot is lower than 1/3 VDD, 555 is set, J1 pulls in, J1-2, J1-3 cut off, they are electric leakage protection. VT1 adopts MOSFET, it is voltage control tube, the static work current Ip is about 0.9mA.



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