555 long delay timer circuit 2

Published:2011/6/20 7:49:00 Author:TaoXi | Keyword: 555, long delay, timer | From:SeekIC

The difference between this monostable delay circuit which is composed of the 555 and the normal monostable delay circuit is the pin-5 of this circuit is connected with the power supply voltage port through the diode D1. So the 555's control port pin-5's (it is connected with the circuit's internal voltage division point 2UDD/3) threshold voltage is improved to 12V-0.7V=11.3V, this makes the charging time of the capacitance C to be extended greatly. The timing time of the figure parameters is 73 minutes. If you press the button, the 555 sets, the relay closes. After 73 minutes, the relay releases.



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