Sunday, 9 December 2018

LED Chaser Circuit with 555 timer

Hello, Everyone today in this article we will discuss LED chaser circuit using 555 timer. You can control two LEDs with this circuit. You Can use this circuit for controlling 2 LEDs you can also change the LED flashing speed. You can also control more LEDs by utilization of 2 N-Channel MOSFETs.

Video Tutorial:

Guys I will highly recommend you to watch my YouTube video about LED Chaser Circuit with 555 timer for more detailed information.

Part Details:

  1. 2 White LEDs
  2. NE555 Timer
  3. 2, 330Ohm Resistor
  4. 100K Resistor
  5. 1K Resistor
  6. 1 DC Capacitor(1,2,3,4....100uf)
  7. 9V Battery
  8. 9V Battery Clip
  9. PCB Board.

Circuit Diagram:

How the circuit works?

  1. The circuit is very simple. you can also make this the number 3 pin is the output pin. Number 3 pin gives the PWM signal which is something about logic 0 and logic 1. Logic 0 means 0 volt and logic 1 means 5 volt. Logic 1 and logic 0 alternates in a fraction of time. I mean if you find that the logic is high then after that the logic will be low after that it will be high and it will go on.

  2. Let's talk about logic 1: The logic 1 and logic 0 is sequential. So was let's talk about logic 1. Logic 1 means 5-volt output. Now if you have read the logic 0 paragraph then you can imagine the logic 1. This is logic 1 so it means that the voltage of PIN 3 is 5 volt. So we can say the middle node voltage is 5 volt. Let's talk about LED 2 first. The middle node voltage is 5 volt and the GND voltages are 0 volt. Show current will flow from the middle node to GND. So we can say the led 2 will run.

  3.  Let's talk about LED 1, let's imagine you have connected the circuitry with 5-volt power supply. Show the Vcc voltage is 5 volt and also the middle node voltages 5 volt so there is no potential difference between these two points so we can say the LED 1 will not work.

  4. This cycle continuous one by one. And the two LED glows one by one.

  5. Here the capacitor takes a great role in switching. Let me explain, the capacity at which you have connected is charging and discharging simultaneously. Firstly the capacitor charges and it comes to a threshold point. The capacitor stores the charge up to the threshold value. When the capacitor crosses it's threshold point then the IC triggers and suddenly the capacitor started discharging. The circle will what till the capacitor fully discharged after that the capacitor fully charged and crossed is the threshold point. And the same circle runs more and more. Here the capacity takes a great part. If you use a capacitor with higher capacity, Then the flashing of the LED will be slower. For this reason, I have used female headers for seeing the changes after changing the capacitor.
      Now you come to the conclusion that we use 555 timer for flashing 2 LEDs. You Can also read the new article about LED Chaser Circuit with 4017 I.C.


  1. Great video pal. Can you please tell me how can blink a total of 18 leds ( 8 on one side & 8 one the other side ) with a 5v power supply. i need it for my bicycle light. please reply. thanks in advance.

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