This circuit operates in the digital circuit.It has 2 inputs are inputs inputs A and B inputs to receive input, By used nand gate ICs,To control the on-off of the lamp.
Operation of the circuit. When the input to the A is listed as “0″ or “1″.And B is listed as “0″ will cause the output of IC1 / 3 to “0″.The Q1 does not work will not light LED1.But if the A is listed as “0″ and B is listed as “1″ will cause the output of IC1 / 3 to “1″ As a result, Q1 LED1 light work.
But if the A is listed as “1″ and B is listed as “1″ will enable LED1 blinking frequency of approximately 3.5 Hz.The principle is working. The first two legs of the conditions IC1 / 1 “0″ to the output Into “1″.And IC1 / 2 off the output is “0″ IC1 / 3 to return to the status output from a “1″ LED1 is light.And caused a charge of C1.This will take and when will fully charge C1 pin 2 of IC1 / 1 is “1″ makes the output from “0″.And IC1 / 2 off the output is “1″ and IC1 / 3 to return to the status output from a “0″ LED1 is extinguished. And caused the discharge of C1 through the voltage of R2 through the voltage of C1 gradually decreased.The voltage at pin 2 of IC1 / 1 to 0 volts of this work will continue, causing LED1 flashes.