Posted on Jun 15, 2012

A positive-going trigger pulse can be used to start the timing cycle with the circuit shown. In this design, trigger input pin 2 is biased to 6V (1/z Vvv) by divider Rl and R2. Control input pin 5 is biased to 8 V (213 Vvvl by the internal divider circuit. With no trigger voltage applied, point A is at 4 V (1/3 Vvv). To tum the timer on, the voltage at point A has to be greater than the 6 V present on pin 2. Positive 5-V trigger pulse V, applied to the control input pin 5 is ac coupled through capacitor Cl, adding the trigger voltage to the 8 V already on pin 5; this results in 13 V with respect to ground.

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

The output pulse width is determined by the values of R, and C,. When voltage at point A is increased to 6.5 V, which is greater than the 6 V on pin 2, the timer cycle is initialized. The output of timer pin 3 increases, turning off discharge transistor pin 7 and allowing C, to charge through resistor R,. When capacitor C, charges to the upper threshold voltage of 8 V (2/3 Vvv), the flip-flop is reset and output pin 3 decreases. Capacitor C, then discharges through the discharge transistor. The timer is not triggered again until another trigger pulse is applied to contrgl input pin 5.

Leave Comment

characters left:

New Circuits



Popular Circuits

Simple 2M 6M Transverter Circuit
Conversion Receiver For 160 To 20M Circuit
Buck Boost Voltage Converter
lamp dimmer
1.5V to 5V/12V DC/DC Converter with LT1073
12 Volt Toilet Tank Refiller
Multiplication detector circuit with MC1496
Compact 100W power amplifier circuit
Low Cost Pulse Generator circuit