This circuit allows to obtain an output pulse independent, in duration, of the action time on switch S1. A possible application is in counters, to eliminate the bumping of the switch contacts, which can be responsible for producing a pulse train instead of just one, when pressed. In this case, two of the 4 NAND ports of the integrated 4001 are used. Diode D1 is general-purpose 1N4148. Note that pins 7 and 14 are connected to the power supply. It is customary to ground the inputs of the other integrated gates if they are not used. In the same figure we show the times obtained for the signals on this circuit. Time t1 depends on the value of capacitor C1, while time t2 depends on the value of capacitor C2. An important characteristic of this circuit, to be observed, is that the output, normally at level HI, remains for a certain time t2 at level LO after the impulse produced by switch S1 ends.
