LED FLESHER CIRCUIT USING CD4011

LED FLESHER CIRCUIT USING CD4011

Summary
This is the small circuit used to flesh two LED after specific interval of time with the help of NAND gate. In this CD4011 is wired in astable multivibrator mode generating 50% duty cycle square wave at approx. 1Hz frequency. This circuit can be used as eye of a toy or can be used as indicator.
Description
This circuit is based on CD4011 IC which contains four independent NAND gate in a single 14 pin IC. To understand the working first have a look on the truth table of NAND gate-

Input		Output
A	B
0	0	1
0	1	1
1	0	1
1	1	0

In NAND gate we will get output when any of the input signals go low and if both are high we will not get output in that case.
Working of circuit is very simple in this we are using all 4 gates of NAND gate. When you switch on the power supply voltage at pin 1 and 2 is high as we can see from truth table output pin 3 become 0 and this is supplied to pin 5 and 6 and from the truth table if both the inputs are low we will get the high output as a result LED connected to pin 4 start glowing. Time period for which it glows depend on the value of capacitor used. If you increase the value of capacitor charging time will increase and LED1 will glow for longer period and if you decrease glowing time will also decrease.
As capacitor connected to pin 3 start charging pin 8 and 9 will receive a high pulse and similar action will take place means pin 10 become low and we get output from pin 11 and LED 2 start glowing and Capacitor C2 charges which is feed back to pin1 and 2 again it become high and whole cycle is repeated.
Note-You can also connect a relay in place of LED so that after certain period of time one device will on and other become off.





Component used

IC
CD4011	1
Resistor
R1,R2(4.7K)	2
R3(330E)	1
C1,C2(470uF)	2
Miscellaneous
LED1,LED2	1