Timer circuit


Posted on Dec 16, 2012

After one cycle of operation, SCR 1 will be on, and a low value of voltage is applied to the UJT emitter circuit, interrupting the tuning function. When pushbutton SI is pushed, or a positive going pulse is applied at point A, SCR 2 will turn on, and SCR 1 will be turned off by commutating capacitor CC. With SCR 1 off, the supply voltage will be applied to RE and the circuit will begin timing again.


Timer circuit
Click here to download the full size of the above Circuit.

After a period of time determined byihe setting of RE, the UJT will fire and turn SCR 1 on and commutate SCR 2 off. The time delay is determined by the charge time of the capacitor.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Zener Oscillator circuits
DC motor 12V speed controller circuit with explanation
Preamplifier + tone control circuit based TDA1524A
power supply variable with lm338
big e stereo parabolic microphone
fotovoor schema
1N4001 Diodes
Ultrasonic Proximity Detector
Yaesu G-400 Antenna Rotator Controller
Astable Multivibrator
Narrow pulse infrared light emitting circuit



Top