LED Flashing Circuit





Introduction: 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

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

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

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



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    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.


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    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.

    It's Great


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

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

    @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)?

    is it possible without a perf board

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

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

    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?

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

    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?


    1 reply

    yes ,thats capacitance from your finger

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

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

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

    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!

    1 reply

    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.

        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.