Changing the pulse width

To contact us Click HERE

Changing the pulse width The previous assembly gives a rectangular signal with a duty cyclic equal to 50 %. We can need to change it to produce pulses for example. A simple means is to use a variable RC circuit and to reshape the signal obtained by means of a Schmidt trigger , here a CD 4093 which allows to use a wide range of voltage. (The CD 4093 is in fact a quadruple logic gates NAND which we use here only the inverter function).
Pin Assignments for CD4093 In1 In1' Out1 Out2 In2 In2' Ground In3 In3' Out3 1Out4 In4 In4' +Vcc		Components List Pot. : P1 = 20 kΩ Capacitors : C1, 33 pF digital circuit : CD 4093 Power supply VCC : 5 to 18 V
Modifying the value of P1 we make vary the height of the signal (B) which is not any more squarewave but sawtooth. The trigger activates when a threshold is reached and we so obtain a modified duty cycle (C and D).