LM555 Timer Circuit

 

LIST


Resistors (all 0.12 watt, ± 5% Carbon)

R1= 1 KΩ
R2 = 150 KΩ
R3, R4 = 330 Ω


Capacitor

C1 = 10 µF/16 V

Semiconductors

D1 and D2 = Green and Red LED Respectively
Miscellaneous
8 pin IC Base

SW1 = Push to on switch

Timer IC NE555 is very popular and most usable in electronics circuit. Timer IC NE555 is also called Ideal IC because it is multipurpose, low power consumption, small size and durable. Mostly there is fault in circuit but our first doubt is on IC because IC is the combination of many more components or IC itself is a combination of circuit. Here is the simple but effective IC tester circuit which check IC NE555 whether it have fault or not.

Working of the circuit timer IC NE555 

In the circuit IC NE555 itself is used as astable multivibrator mode. Switch SW1 is pushed for power supplies which charge the capacitor C1 through resistor R1 and variable resistor R­2 which trigger IC and high output is obtained from pin no 3 which glow LED D2 (LED D1 off). Similarly when capacitor is discharged the output become low and LED D1 glow (LED D2 off). The on and off of LED in sequence is in practice until power supply, this mean there is no fault in IC. But if the LED is not glow or on and off in sequence then there is fault in IC.



1. Data sheets NE/SA/SE555/SE555C

2. Advance used NE555

     2.1

      2.2  Driver LED circuit for Indicator using


     2.3 Night Rider




       2.4  More