Introduction: LED Flashing Circuit

Picture of LED Flashing Circuit

I will show you how to make a LED circuit that make LED flash at different intervals depending on the capacitor size.

Step 1: Materials

Picture of Materials

What you will need:
-Soldering iron
-2 1kilo-ohm resistor
-1 110 ohm resistor
-1 10 to 1000 uf capacitor
-Perf board
-1 or more LED's
-1 555 timer
-1 9volt battery clip
-1 9volt battery

Step 2: Scematics

Picture of Scematics

Here are schematics the red in the color one is for positive.
You can put a capacitor of diferent sizes depending on how fast you wan it to flash.
Ex:A 10 uf cap will flash really fast but a 1000 realy slow,I would suggest a 330 uf cap.

Please don't hate it was done in paint.
P.S. It's 10 to 1000 uf capacitor.

Step 3: Finished Product

Picture of Finished Product

Now that you done soldering the component on the perf board your circuit should resemble like this one.


randofo (author)2008-02-21

Hello, and welcome to the Instructables community! It's great that you've decided to tell the world about something you've made by publishing an Instructable. We just wanted to let you know that your project still needs a little more work if you want it to be well received on Instructables. Projects that don't include certain basic elements tend not to get the attention that they deserve, and so we'd love for you to check out the list below of what makes a successful Instructable. Successful projects on Instructables include: - clearly written details of a finished project with instruction - as many steps as are necessary to explain your project - clear images that you took of your project for most, if not all of your steps - an intro image - proper spelling and grammar - appropriate cautions or safety considerations I'll give you another opportunity to make any final changes to your project before we publish it. Once you're all set to go, please republish your project and send me a quick comment letting me know that you've made some changes. I'll give it a quick final check to make sure you're on the right path, and then remove this note. Thanks for your submission and we hope to see your project published soon!

Joey Geisler (author)2016-08-16

I need a built circuit that works if anyone has the time.

I am a retired vocational instructor with a need but no time to construct. Anyone out there that can help??? I'm in Branson, Mo.

Circuit must turn on (blink) every 10 to 15 seconds. Be able to run for weeks w/o burning out. 12 VDC in an automotive situation. This is to help keep my parked truck from getting broken into. It should help where I am.

One LED (blue or red) I'll mount the LED on top of my dash. So it will need 10" leads for the LED and be mounted in a LED plastic mount.

No to spam!!!!

JennerP (author)2016-01-05

can you make one for 12v? I tried doing this but it doesn't seem to work with 12v; neither have I tried connecting it to 9v.

SmitP2 (author)2015-10-10

It's Great


goutam.hegde.359 (author)2015-03-28

Can you explain the circuit or a link having explanation is enough

haaglm (author)2013-10-05

could you use a potentiometer in place of the capacitor to make the speed at which it flashes adjustable

firefly762 (author)2013-03-02

@deepuelmil: Anything is possible without perf board, it just makes it easier to organize your components and it looks nicer than a tangled mass of wires :P

My question: about what size capacitor would cause the LED's to flash at approx. 1Hz (aka on/off cycle takes about a second to complete)?

deepuemil (author)2012-12-10

is it possible without a perf board

innocentsaif (author)2012-06-07

can you give the clear picture of step 3 without any labels!

sukhmanattwal (author)2012-06-01

thank you soooo much :)
this was a great help !

netfreak11 (author)2012-05-17

This circuit is really good and way better. . .
One thing I want to ask is that if I want to use the same circuit for having my LED turned on for 1 second and having the same LED turned off for 1 second as well for indefinite period of time then what valued capacitor or resistor etc should I use?

robotmaker (author)2012-04-24

also from the circuit you left pi4 trig un-connect shouls always pull high or it will re-trigger

Ghost915 (author)2011-07-26

I found your schematic and it's just what I was looking for but, I found that by touching the top of the 555 timer chip it turns it on and off and controls the flashing. Is this suppose to happen?


robotmaker (author)Ghost9152012-04-24

yes ,thats capacitance from your finger

callones (author)2011-03-31

Tries this and it works well. what if i want it to have a lower duty cycle? what do i need to change?

robot1398 (author)2011-02-22

i have made it and it works great.
i used a 100 uf capacitor

prajwaltinkle (author)2011-01-09

my led just lights up but doesn't flash/blink at all.....please advice.....

tomx63 (author)2010-11-09

my experience with this type of circuit is that the on/off intervals are equal in length. do you know how it can be accomplished to increase the off interval? say so that the LED blinks quickly once every 3 seconds.
and great job with this instructable!

tomx63 (author)tomx632010-11-15

figured it out over the weekend. the combination of capacitance and resistance (excluding the LED resistor) tweaks the IC to set the desired flash intervals.

y2knemesis (author)2010-03-17

    i wanted to know,what capacitor should i use to make the light blink like 60 times a minute and the reistor needed to use on a 12v supply.thanx.great work keep it up.

steven123654 (author)y2knemesis2010-09-22

look it up on the net there is lost of post on the 555 and formulas for the timing

LastDevil (author)2009-06-12

Sorry for this dumb question but what will i need to make it a 12v input power?

steven123654 (author)LastDevil2010-09-22

you shouldn't have to change anything

steven123654 (author)LastDevil2009-06-28

Change the resistor between the 555 and the LED to a higher value, 1k ohm is safe.

tacoman101 (author)2010-09-19

Hi, I so if I use a 3V source to power a led will I need the 1k resisters?

steven123654 (author)tacoman1012010-09-22

No you shouldn't but I don't think the 555 will work under 5volt look up on a data sheet

max1zzz (author)2010-04-02

 if i replace the led with a transistor could i use it to turn stuff on and off

steven123654 (author)max1zzz2010-09-22


brettboy01 (author)2010-08-28

what capacitor would i need for it to blink 20 times a second because my friends halucinate when i flash lights in their eyes

jamilm9 (author)2010-03-21

I just made this in 10 minute. It turned out great. Thanks 

matstermind (author)2009-09-11

does it matter what voltage the capacitor is?

darkjester0130 (author)2009-07-11

I am curious, I was wondering how to make a circuit with 4 lights, in which only one light would light up at a time and go in order from one, two, three, four, and then back to one. Also, is there a way to adjust speed on that and do the same thing with 8 or more lights?

fkuk (author)2008-06-08

what capasitor do i need to make it flash slower about once every 5-10 seconds

stefannasehi (author)fkuk2009-06-12

did he say 10uf to 1000uf or 10uf to 330uf?

steven123654 (author)fkuk2008-06-12

you would have to try and see but it think higher then 300 microfarad should do but not sure.

ak11667 (author)2008-12-27

hey i was doing some tinkering with this circuit learned by using a 100microfarad cap and a 10k potentiometer by upping the resistance you can modify the length and duration of the blinks you replace the 2 1k ohm with the pot and it will blink according to the pot

armadillozenith (author)2008-03-13

Haven't tried it yet. But this is really useful idea, just what I wanted to find for making very simple cheap flashing light effects for sci-fi props (maybe accessories for a costume party or parade). I think I already have what I need except for 555 timers. For me, this level of Instructable is fine. Thanks!

I will soon be posting a project that uses the same circuit but with a relay for higher voltage,that may be useful for your props.

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