Programmable Timer Circuit. The circuit is built around three quad two-input NAND gate ICs CD4011 (IC1, IC3 and IC5), two 14-bit binary ripple counters CD4020 (IC2 and IC4) and a relay driver ...

555 Timer Delay Off Circuit Diagram. The above circuit uses a 555 timer U1 in mono stable mode. If once push button is pressed, it drives pin2 of timer momentarily to ground that triggers the 555 to ...

A 4011 Quad 2 Input NAND Gate was used for IC1, but many other CMos gates or inverter arrays can be used in its place, e.g. 4001, 4002, 4025, 4012, 4023, 4049, 4069. With these devices, all inputs ...