555 LED Flasher: Everything You Need to Know


A 555 LED flasher provides significant visual light effects for everyday applications. For example, it can integrate into police lights, strobes, SoS circuits, etc. Indeed, these typically rely on a 555 Timer IC to continuously produce flashing and fading sunlight. Additionally, it depends on various electronic components to help create the display. You can also modify this implementation to develop an improved LED flashing circuit. Developing this type of project can seem a bit difficult to grasp. This article will put you on the right track toward understanding an LED flasher. So let’s get started!

1. How does the 555 led flasher circuit work?

Flashing lights commonly utilize a LED flasher circuit

(Flashing lights commonly utilize a LED flasher circuit)

With a 10% duty cycle, the 555 IC timer sets to the astable multivibrator mode. Generally, this occurs when it connects to an electronic circuit. In some projects, the LED will briefly activate and switch off for longer.

A different LED connection will cause the duty cycle to reverse, however. Battery consumption also increases because the LED activates for a longer time. Moreover, connecting a 220K potentiometer in series with a 22K resistor produces a variable flash rate.

2. Pin Description of 555 Timer IC

(555 timer IC pinout. Red represents power pins, blue represents output, and the green represents input pins. Source: Wikimedia Commons)

We included the pin description of the 555 timer IC in the table below:

We included the pin description of the 555 timer IC in the table below:

3. How to Build a 555 LED Flasher?

This section details how you can create a 555 LED flasher.

(Circuit diagram for a 555 LED flasher)

You will need the following electronic components to build the 555 LED flasher:

  • 9V battery – 1x
  • 555 timer IC – 1x
  • LED – 1x
  • 1µF Capacitor – 1x
  • 1k Ohms resistor – 1x
  • 470k Ohms resistor – 1x
  • Breadboard – 1x
  • Connecting wires – 12x

Also, follow these steps to create the circuit:

Follow these steps to make the circuit:

Step one:

Image showing a 555 timer IC

(Image showing a 555 timer IC. Source: Wikimedia Commons)

Put the 555 timer IC on the board. Next, attach the 555 timer IC’s pin 1 to the ground.

Step two:

This image represents a polarized capacitor with anode and cathode references. Source: Wikimedia Commons

(This image represents a polarized capacitor with anode and cathode references. Source: Wikimedia Commons)

It’s important to note that the polarized capacitor features a negative and positive end. While the opposing end represents the longer lead, the positive end represents the shorter lead. Thus, you will need to connect pin 2 to the capacitor’s positive future. Next, click the capacitor’s opposing end to the battery’s ground.

Step three:

LED anode and cathode

(LED anode and cathode. Source: Wikimedia Commons)

Next, you will need to short pin 2 and pin 6 together. Then, add a 1k Ohms resistor to connect with the 555 timer IC’s pin 3 and the LED’s positive lead. Additionally, you should ensure the LED’s negative information relates to the ground.

Step four:

(A 9V battery with positive and negative terminals.)

Afterward, form a connection from pin 4 to the battery’s positive terminal. Meanwhile, pin 5 remains disconnected.

Step five:

470k Ohms resistor.

(470k Ohms resistor. Source: Wikimedia Commons)

Use the 470k Ohms resistor to form a connection with pin 6 and pin 7. With a 1k Ohms resistor, connect pin 7 to the battery’s positive terminal.

Step six:

Create a connection from pin 8 to the battery’s positive terminal. Lastly, connect each battery lead to the breadboard. And this will supply power to the circuit.

4. Applications of 555 led flasher

Some applications for the 555 LED flashers include:

  • Strobe lights and SoS signal circuits
  • Car light indicators
  • Wiper motors
  • Turning indicator circuits for vehicles and cycles
  • Counter circuits

5. More 555 led flasher circuit projects

We also included two 555 LED flasher circuit projects below:

 Making a Police Revolving Light Effect

Circuit diagram of a police revolving light effect

(Circuit diagram of a police revolving light effect)

This circuit generates the same illuminating, revolving light you see on a police car. It mainly relies on a resistor, capacitor, and Zener diode to produce the effect. As illustrated in the diagram, these components connect to the circuit’s output. In particular, this setup has flashed on the LED. In development, the LED will brightly illuminate. Afterward, it diminishes in brightness while periodically providing a high-intensity pulse. And this imitates the police’s warning light.

 Random Light Effect Generator Circuit

Random light effect generator circuit diagram

(Random light effect generator circuit diagram)

The circuit, as shown above, generally produces irregular light sequences on the LED lights. Three LEDs attach to the course, along with two resistors and a capacitor. Additionally, two LEDs are connected in parallel, opposite each other. These will also blink at intervals, following a specific rhythm. Meanwhile, the third LED will flash at a randomly different rate.


Not only does the LED flasher produce a great visual display, but it also serves a purpose for many applications. For example, you can utilize this implementation to create a patterned light effect. In that case, it can generally imitate a police light or SoS strobe. You will also need to remember that this typically relies on a 555 timer IC to generate the effects on each LED. Of course, you can build any LED flasher circuit as a DIY project, which can be very rewarding!  

Do you have any questions regarding a 555 LED flasher? Feel free to contact us!

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