555 multifunction household appliance protector circuit(2)

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

As shown in the 10-15, the protector circuit consists of AC hypotension, DC steady voltage circuit, undervoltage, overvoltage detection circuit and power-off delay circuit, relay control part. A monostable dalay circuit is composed of 555 and C4, R4. When it is connected to power supply, due to the voltage on C4 can not suddenly changed, 555's 2 foot and 6 foot have a positive peak pulse voltage, then 555 is in reset state, output terminal 3 foot is low level, relay J is in release condition, the socket CZ has no electricity. With C4's charging, when 2 foot level is lower than 1/3 VDD triggrt level, 555 is set, 3 foot is high level, J pulls in, J1-1 adherent point is closed, the socket has electricity, the electric appliance works.



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