LED Blinking Circuit using 555 Timer

This is simple LED Blinking Circuit using 555 Timer.

It uses 555 timer IC.

Circuit make LED ON and OFF again and again.

Good for beginner to learn 555 timer working.

It needs few parts only and run from 9V battery.

This circuit is easy to make and is a small fun project.

Circuit Working:

Parts List:

555 timer work in astable mode in this circuit.
.
Output goes high and low again and again.

When output is high the LED is ON.

When output is low then LED is OFF.

Blink speed depend on resistor R1, R2 and capacitor C1.

C1 charges and discharges and make led blink fast or slow.

Formulas with Calculations:

Formula for astable mode:

Ton = 0.693 × (R1 + R2) × C1

Toff = 0.693 × R2 × C1

Total time t = Ton + Toff

Frequency f = 1 / t

Example:

R1 = 1k, R2 = 10k, C1 = 10µf

Ton = 0.076s, Toff = 0.069s

t = 0.145s, f = 6.9hz

LED blinks around 7 times per second.

How to Build:

To build a LED Blinking Circuit using 555 Timer follow the steps below for connection:

• Take all parts same like is circuit diagram.
• Pin 1 goes to ground.
• Pin 2 trigger connect to capacitor C1.
• Pin 3 output connect to LED by resistor R3.
• Pin 4 reset connect to +9V.
• Pin 5 control pin connect to capacitor C2.
• Pin 6 threshold join with pin 2.
• Pin 7 discharge connect between resistor R1 and R2.
• Pin 8 Vcc connect to +9v battery.

Conclusion:

This is an easy and low cost LED Blinking Circuit using 555 Timer.

By changing R2 or C1, we can change blinking speed.

It is a good experiment to learn 555 timer working.

References:

Alternatively blinking two LEDs with 555 Timer