555 multifunction household appliance protector circuit(1)

Published:2011/6/9 9:02:00 Author:nelly | Keyword: multifunction household appliance protector | From:SeekIC

When it comes undervoltage or overvoltage state, D2 or D1 turns on, IC's 2 foot and 6 foot are high level(>2/3 VDD), then 555 circuit is turned reset, 3 foot output is low level, relay J is released, J3, J4 are cut off, the household appliances are protected, at the same time, LED lights. The delay ON circuit is composed of C3, R4, R5 and 555, when it is turned on or instantaneous power failure, the voltage on C3 can not suddenly changed, 555's 2 foot is positive peak voltage(>2/3 VDD), then 555 is in reset state, 3 foot is low level, J has no action, socket CZ has no electricity. LED1 lights. With C3's charging, when the electric potential of 2 foot and 6 foot is lower than 1/3 VDD triggrt level, 555 is set, 3 foot is high level, J pulls in, J3, J4 are turned on, household appliance socket has electricity.



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