Thursday, August 23, 2012

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On-Off Touch Switch Using IC CD4011 Circuit

This is a circuit of electrnic on-off Touch switch controller using IC CD 4011 that is connected as a FLIP-FLOP. He is simple in the manufacture and the materials that use they exist everywhere. This based in the known CD 4011, which drives a relay of which the contacts play the role of switch. The metal surfaces can have what form we want, but it should they are clean and near in the circuit. In order to it changes situation it suffices touch soft somebody from the two plates.
On-Off Touch Switch Using IC CD4011  Circuit
 CD4011 (IC FLIP-FLOP) Pinnning
This high sensitivity of the circuit makes the touch switch  operation possible. The two gates are held at logic state «1» continuously by means of the two resistors R1 and R3 that connect them to the positive supply rail. These resistors have a very large resistance of 10 Mohm. If we now touch a set of contacts the skin resistance closes the circuit between the corresponding gate and the negative supply rail. The skin resistance for small areas of the skin is normally much lower than 10 Mohm and the gate is effectively brought to logic condition «0» which makes the FLIP-FLOP change state. For any given state of the FLIP-FLOP touching the corresponding set of contacts will make the circuit to reverse its state of balance and in effect toggle the switch. As a switch is used a relay driven by a transistor which is driven from the out put of the FLIP-FLOP.

List Component Of On-Off Touch Switch Circuit
R1  : 10MOhm 1/4 W
R2  : 10MOhm 1/4 W
R3  : 1KOhm 1/4 W
D1  : Led red
D2  : 1N4148 diode
TR1 : BC558 PNP Transistor – BC327
IC1 : CD4011 CMOS IC
RL1 : 12V relay rated at 250 V / 2A 

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