Touch Switch Circuit

Posted on Jan 11, 2013

When the touch-on contacts are bridged, pin 6 of Ul-b goes low, which forces its output (the set output) at pin 4 to go high. That high divides along two paths; in one path, the output is applied to pin 2 of Ul-a, which causes its output at pin 3 to go low. That low is, in turn, applied to pin 5 of Ul-b, which latches the gate in a high output state. In the other path, the output of Ul-b is used to drive Ql. When Ql turns on, U2`s internal LED lights, which turns on its internal, light-sensitive, triac-driver (diac) output element.

Touch Switch Circuit
Click here to download the full size of the above Circuit.

The triac driver feeds gate current to TR1, causing it to turn on, and light the lamp (11). When the off contact is bridged, IJl-a`s output switches and latches high, causing Ul-b`s output to go low, turning off the lamp.

Leave Comment

characters left:

New Circuits



Popular Circuits

RS-232 surge protection
Optical Interruption Sensor
Door Lock Wiring
12V Inverter Circuit Using 4013
switching power supply 2
dev board
MOSFET + Relay to Control a Motor
RF amplifier circuit diagram
Medium-Power FM Transmitter
Active ferrite rod antenna for HF
Laser power supply circuit