On Off Touch Switch Circuit

Description 

 The modern mechanic switches are improved concerning of old technology. We need however many times to replacement some old switch or to check currents bigger than the durability of certain switches or simple we need something with modern appearance. For he and different reasons is essential the up circuit. It is simple in the manufacture and the materials that use they exist everywhere. 

Circuit Diagram:

Parts:

• R1 = 3.3M
• R2 = 3.3M
• R3 = 10K
• R4 = 1K
• C1 = 10nF-63V
• D1 = 1N4007
• D2 = Red LED
• Q1 = BC547
• IC1 = NE555
• RL1 = 12V Relay

Circuit Operation:

 This circuit is based on the well known timer IC 555 (IC1), 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. Plate MP1 in order to the contacts of RL1 close [ON], or plate MP2 in order to the contacts of RL1 open [OFF]. The current that RL1 will check depended from his contacts. The Led D2 turns on when the switch they are in place ON and the contacts of RL1 closed. Two small pieces of metal can be used instead of MP1 – MP2. Because MP = Metal Plate.

Source http://www.extremecircuits.net/2009/08/on-off-touch-switch-circuit.html