19 LED flasher circuit using 555 IC

This project is a flashing led circuit powered by 555 timer IC.This
flasher circuit is composed of two versions, the simple led flasher 
that uses only two LED, and big flasher that consists 20  LEDs.

Simple LED Flasher circuit is powered from a 6V to 12V
battery and delivers a current of about 20mA to LED. The 
frequency of the flashing on both LED is controlled by 100K
potentiometer connected between the discharge and trigger pin
of 555 timer IC. The rate of flash ranges from 1blink per 2 
seconds up to 10 flashes per sec.
simple LED flasher schematic
Big LED flasher circuit is composed of 20 LEDs and uses transistors
as the driver and amplifier of the pulses generated by the 555 IC. The 
npn  general purpose type (9013, 2N222, etc), so is the pnp transistor
(9012, BC557, etc) If the supply voltage is 6V, R1and R2 =27 ohms 
while R1 and R2 = 200 ohms if supply voltage is 12V.

Big Led Flasher schematic
You can change the frequency of the flashes by changing the values
of resistors and capacitor using the 555 timer calculator.

If you planning to build up to 300 LED per group just replace the part of the schematic above with this. See diagram below. Power supply used is 12V.

Note: The type of LED can be of any color such as red, green, orange, yellow but not blue or white LED.
          Blue or white LED requires much higher forward voltage to light.


  1. But if I wat to use 300 leds in each group? Wich is the electronic scheme?

  2. I have added a modification above if you are planning to build the circuit using 300 LED per group.. just take note that the circuit above is good only for low power LED. If you are planning to use white , blue or any LED that requires much higher forward voltage, just post a comment and i will modify it for you..If you are not so sure with the type of LED you are using, just look for its specs on a datasheets. The important thing to know is its forward voltage and maximum current.. tnx

  3. Thankyou very much for your help with 300 leds corcuit. I I will have more questions I will let you know.

  4. Hi,
    Your circuit looks good, if i need to add about 150 led red and 150 led say green or white, what changes needs to be done also, can this circuit be powered by mains (no transformer)

    thanks in advance

  5. Hi,
    If you have 300 per group also is fine, (only specify what colour led i need to use)but only it should be 230v ac powered with necessary changes.

    thanks in advance

  6. HI,

    I made this circuit, but using all resistors at 220 ohms (only 220 ohms is available in the market), if the complete circuit is connected, then all the leds glow, but dont flash, if the red leds are disconnected (transistor 2n222) then the greens glow and flash, but the variable pot is unable to vary the flashes.

    Any advice.

  7. hi,
    Regarding to the value of resistance, it is a strict requirement that you follow the exact or nearest value to make the circuit works.You cant replace a 5k resistor directly with a 220 ohm resistor unless you series 23 pcs of 220 resistor to make an equivalent resistance of 5k.

  8. this is a very nice and helpful circuit design. i just have a question, im planning to make a light bar for my rescue vehicle. there will be two groups, 150 red and 150 blue. can you modify the circuit so it can accommodate low power and high power LEDs? im planning to use my vehicle power of 12v do i need a regulator circuit?

  9. nice circuit, the batry of 9v will be flat quickly or it will flash for ling time?

  10. It depends on the capacity of your battery. A new 9V battery will last for more than a day (around 27 hours) powering simple led flasher.
    Higher capacity batteries like 6V 4.5Ah can last around 20 days.



  13. Using 2N3055 (for TIP41) and MJE2955 (for Tip42) actually is best since these transistors provide more power and higher current rating. You can replace also the transistor with any transistor with the same or much higher capacity.

  14. The first circuit shown on here, the simple 2 LED one, has a short. When both LED's are connected according to that schematic, it will short the 2 LED's in series to the power supply blowing both LEDs. You need two different resistors on the output of the 555 and each going separately to each LED.

  15. Greenwich Coffee DudeMarch 30, 2012 at 5:22 AM

    How about a 556 flip-flop circuit were it switches between 10hz and 15hz every second? MOSFET switches to pass some higher current loads?

  16. DH-gm,
    I want to make five identical circuits like the one above but with 48 leds in a group for each circuit. Three of the circuits have 3.0-3.4V leds and the other two circuits have 2.0-2.4V leds. All of the leds run at 20mA. I only want one set of flashing leds per each of the five circuits. Im also running all of the five circuits in parallel to eachother on a 12V 2Amp DC power supply. Can the circuit above be modified to control my circuits? Heres a link to the exact 555 IC im using (http://www.taydaelectronics.com/datasheets/A-032.pdf. Also can I dim all of the leds by putting a potentiometer in the circuit that controls all five groups? If I can, where do I need to put it, and what value does it need to be?


  17. Does this two group flash at the same time or alternately? If alternately, how can I make i flash at the same time

  18. for the 300 LED, do you still need just 1 555 IC?

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