Introduction: Flashing L.E.D. Using 555 Timer

I was trying to put in a video but it didn't work for me, so here is a link to YouTube
This is a detailed instruction showing how to build a flashing L.E.D. using 555 Timer.
There is no knowledge of electronics required in order to complete this project.
All the parts needed are listed, priced and links to them are also included. 

There are two sets of pictures, the top shows the progression of the project and the bottom shows each step individually.

This is my first instructable and it is also an assignment so please leave comments.
Thank you.

Step 1: Parts List

Here you will find a list of all required parts, their pictures, prices and where to get them.
There is also an excel file attached.

1. Breadboard
2. 9v Battery
3. Battery clip
4. Jump Wires
5. 555 Timer
6. Capacitor 1μF
7. Resistor   1k Ohm            x 2 (brown, black, red)
8. Resistor    470k Ohm            (yellow, purple, yellow)
9. L.E.D.

Time needed to finish this project: 5 - 10 min.

All the above parts can be bought at next day delivery (Ireland).

Step 2: 555 Timer Pin - Out and Breadboard Layout

First picture shows a pin-out for the 555 Timer. This will be needed in order to connect the chip.
The second picture shows how the paths in the breadboard are connected.

Step 3: Putting All Together

This project contains small parts which can be ingested or inhaled, so keep away from young children.

Make sure to push all the parts in to the breadboard that they make contact with it.

1. Place the 555 Timer chip in the middle of the breadboard, make sure to put it in the right way round other wise when you will connect the battery the chip will burn.

2. Using short length of jump wire connect Pin 1 (negative) to the bottom row of the breadboard   (ground).

3. Connect Pin 8(positive) to the top row of the breadboard (VCC).

4. Take another length of jump wire and connect Pin 4 with Pin 8.

5. Identify the legs on the capacitor C1, the short one is the negative and the long one is positive. Connect the positive leg to Pin 2 and the negative leg to the ground (GND).

6. Now connect Pin 2 with Pin 6 using piece of jump wire.

7. The resistors can be connected either way round. Using the 470k Ohm (R1) resistor connect Pin 6 with Pin 7.

8. Take the 1k Ohm (R2) resistor and connect Pin 7 to VCC.

9. Connect one end of the second 1k Ohm (R3) resistor with Pin 3 (output) and any empty row on the breadboard (this resistor will be connected with L.E.D. in the next step).

10. Identify the legs on the L.E.D., short one is the negative(-) and the long one is positive(+). Connect the positive leg with the resistor and the negative leg to the GND.

11. The final step is to connect the battery clip, the red lead to the VCC and the black lead to the GND. Connect the 9v battery and enjoy the effect.


AmarjitS6 (author)2017-05-09

Sir how many LED can be connected with 9v battery as a flash light

variousred (author)2016-11-13

I built this and it works great! I added in some potentiometers and i
can control the speed of strobe. I then added a circuit on the other
side of my bread board with a little rumbler motor with variable speed
as well. Then i can control the speed of the strobe and get the motor to
have cool optical illusions when the frequencies match or are slightly

Now i want to change the LED out for a led strip
with 60 leds — which calls for 12v at 1.5amps. I tried hooking up a
power supply with 12v at 1 amp and the led strip and i fried my 555.
woops. How can I handle more juice?

sapt86 (author)variousred2017-04-24

If you want to add an LED strip, add it on Pin 3, that is before the resistor to the output Single LED. The resistor lowers the voltage.

sapt86 (author)sapt862017-04-24

Take positive for LED strip from Pin 3 before R3 (1k ohm
resistor). Connect the Negative end of LED strip to ground.

555 can
operate between 4.5 v and 16 v (SE555 maximum is 18 V). So your 12 v should
not have fried 555. I used 16 v input and it worked fine.

Check this for specs from Texas Instruments on 555.

azharko (author)2017-02-17

does one need a programmer to program a 555chip and also can a 555 chip be programmed using a programmer like arduino ? thanks.

bjefford (author)azharko2017-04-09

The 55 chip is a collection of logic gates which allow you to set a cycle of on/off for the output pin. The greatest extent you can use a 555 is to make an LED flash or to add a timing function to a project. Smarter programmable chips like the processor in an arduino have a similar internal structure but are many times more complex.

bjefford (author)bjefford2017-04-09

*555 not 55

jaycei made it! (author)2017-03-21

Works fine, if you want to speed up the flashing add some more capacitors in serie or buy other ones

NickS212 (author)jaycei2017-03-25

Instead of adding more capacitors, you could just choose lower value capacitors. The frequency can be calculated with the equation 1.44/((R1+2*R2)*Capacitance(Farads)

juiceman74 made it! (author)2017-02-21

Very friendly tutorial with a detailed picture break down. You can add resistor - capacitor matches, which will change the blinking speed, and also add resistor band colors if you like. Thanks for the good job.

FirmanJml made it! (author)2017-02-07

Great, i tried this circuit on my first attempt homemade PCB.

JeffD158 made it! (author)2017-02-05

I had a little trouble only because I didn't know that my breadboard was divided into 4 sections so that there was no connection between the power on the left side of the breadboard and the right. Once I move the power leads to the correct quadrant, the light flashed like a charm. Thanks for the instructable!

dispatj (author)2016-04-25

I made the circuit on my breadboard using various types of Capacitors, it worked really great.

jaycei (author)dispatj2017-01-21

Does 10μf work?

FilipU1 made it! (author)2017-01-18

work to me

bdeutl made it! (author)2016-11-27

Works for me.

Yakasaib (author)2016-10-13

i tried to recreate this on the autodesk online electronics lab. when i simulate it it says that current through led is 307mA while maximum is20mA

Jack-LamarR (author)2016-06-05

My LED won't blind. I do not have a 1uF capacitor. I have a 0.1uF; is this the problem? Help.

ismash (author)Jack-LamarR2016-09-14

You've now increased the frequency at which the LED is flashing to faster than your eye can see. Try plugging the values you're using into the time = R*C equation.

ktorbeck made it! (author)2016-07-26

Still waiting for the PCB to arrive, but everything worked on the breadboard.

EFDG123 (author)2016-05-20

I doing it's don't but i smell not good?

like fire in led.

kevindiamond1015 (author)2014-09-09

i made it but changed the led and resistor (for the led) to a motor that does 1.5-3.0 volts. it worked at first but then the ic overheated and didn't work anymore. i also changed the R1 and R2 to resistors to 47k and 10m ohm resistors. help please!

btw, i burnt my finger :D


ps, i think i connected it wrong. but now i have a different problem. my motor stays on. IT WILL NOT PULSE!!!! HEEEEEEEEEEEEEEEELP!


What type of motor?


@kevindiamond1015: the 555 timer integrated circuit is not designed for the higher current draw of an electric motor. To safely drive a motor, you need additional circuitry, either a power transistor, optoisolator or relay. The power transistor option is the most common. have a look at this design

joeyerica.clark (author)2014-08-20

I followed your instructions to a T. Though some of the values on my resistors and capacitors are a little different. The light flashes but is very, very dim. When I connect to light directly to the power source the light shines good and bright. A

Any ideas why the light is so low when placed in the circuit????


Use lower K resistors.

SaeedH1 (author)2015-07-10

i made this circuit and it works . thanks a lot .. i changed the value of capacitor and resistance so that the blinking becomes more fast its amazing .

visit my page

Climberirw (author)SaeedH12016-04-10

What was the resistance of the resistors you used?

Climberirw (author)2016-04-10

How do I make the LED flash faster?!

Climberirw (author)2016-03-31

What will happen if you don't use a capacitor?

Climberirw (author)2016-03-31

What will happen if you don't use a capacitor?

deltaboss made it! (author)2016-03-04

1. I didn't have a 470K resistor so i added a 150K and 330K in series for a 480 and it works almost the same as when I simulated it in 123d circuits. I added my own twist to it by having a pushbutton between the diode and ground connection so it only works when I hold it.

Smoog (author)2016-03-04

Please I need a circuit that beeps with buzzer, continuous beeping ... Thanks

Boop529 (author)2016-02-26

How would I make it blink faster with shorter equal bursts.

Physics Rabbit (author)2015-07-20

what does pin 5 go to?

LukeK17 (author)Physics Rabbit2016-01-30

Pin 5 is 'Control Voltage'. It's not used in this example. Having said that, I would put a .01uF capacitor from it to ground. Basically, you'll get a much cleaner square wave.

plutten (author)2015-10-28

This works fine.
What do I have to change if I use 12v power?

LukeK17 (author)plutten2016-01-30

I should have also mentioned that most LED's can safely (without burning out) handle around 20mA of current. So, if you're using a 12V supply, keep the resistor value 510+ Ohms. Note: (12 - 1.7) / .020 = 515, but using a 510+ Ohm resistor won't hurt.

LukeK17 (author)plutten2016-01-30

Providing your capacitor is rated for 12V+, you wouldn't need to change anything. Remember, the voltage at pin 3 is roughly 1.7V less than VCC - so, 10.3V. Using the same 1K resistor, you'd be putting 10.3mA through the LED, which is fine. It will just be a little brighter. OHM's Law, my friend. :)

subzero69 made it! (author)2016-01-19

Did what a few other mentioned about swapping a few components. Swapped out the 470k resistor for a 10k pot. Swapped 1uF for a 47uF. This will all fit nicely onto some proto board and then will be a 555 tester for me. The 10K pot gives me a great slow flash all the way up to constantly on in effect.

keithfiore made it! (author)2016-01-03

Thank you for posting this tutorial. It was well written and easy to follow. I used an 8mm 0.5W "water clear" red straw hat LED.

lparsley made it! (author)2015-12-17

it works!!

EnP1 (author)2015-10-18

Used this and put in a speaker instead of led.
Couldn't find the right capacitor so I took 3x3,3 uF in series.
Also put in a POT between the caps and ground.
Sounds goood :)

darivanh made it! (author)2015-10-06

Thanks! I made it as instructed and could not get it to blink. Read some of the comments and changed R1 to 100K and it's blinking (pretty fast, but it's actually blinking!)

blinking LED.jpg
darivanh (author)darivanh2015-10-06

Also changed the capacitor to 10uF

Racersims (author)2015-10-01

Thanks for this will be trying tonight when I get home, am looking to get a flickering light in the end

BondB (author)2015-09-07

use 330 ohms before led it will glow bright if you want morel life and less glow use

higher value of resistor. use a capacitor before resistor 0.1uf. it will discharge slowly

Daveatz (author)2015-08-22

Hopefully this will be of use to someone... This circuit works perfectly, only with mine the LED was really dim. I spent a long time playing around with different resistor values, even replacing R3 with a jumplead. In the end I thought I would try and work out the correct resistors the "proper" way. I put the LED on a bench PS to find out what current it was drawing, it went up to 60mA and popped, dim all the time. You've guessed by now, a faulty LED. Changed it, all works fine. I now use the circuit in a small project box connected to a 12v Pb battery as a visual reminder to disconnect the battery when I've finished playing with it. Circuit works fine at 12v with the LED drawing 1.2 mA, around 14mw.

Ecila28 (author)2015-08-04

it's not blinking </3 how can I make it blink ? without changing the materials?

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