An Easy to Make, Cheap and Simple LED-blinky Circuit With CMOS 74C14




Introduction: An Easy to Make, Cheap and Simple LED-blinky Circuit With CMOS 74C14

About: I like to play with electronics and other fun stuff, modify things to make them more useful or just more funny, putting things together that seem not to fit to make funny stuff. Sharing ideas make the world ...

Sometimes you need simply some blinky LEDs, for chrismas decoration, blinky artworks or just to have fun with blink blink blink. I'll show you how to make a cheap and simple circuit with up to 6 blinking LEDs.

Note: This is my first instuctable and i'm not a native english speaker - so please excuse my mistakes.

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Step 1: Parts You Need

So you need some cheap electronic parts, here we go:

- 1 CMOS 74C14 - its a small and really cheap microchip, we use it to create oscillators to make our  LEDs blink
-  some jumper wires
- a breadboard to stick the parts on it
- a 9V block battery with batteryclip
for further experiments a potentiometer around up to 1 M

for every LED-Circuit (you can add up to 6 to one chip) we need
- an LED ;-)
- a capacitor (around 4,7 µF, you may vary the value to get different blink frequencies)
- a resistor 100k-200k
- a resistor to limit the led current, around 1-3k

Step 2: Okay Lets Stick It Together

lets go to our first blinky cirtcuit. Place the CMOS Chip in the middle of the breadboard as shown on the image.

Connect pin 7 of the chip with the ground (-) and pin 14 with the VCC (+)-bus on the breadboard.

Now connect the capacitor to pin 1 and the ground (attent to the direction, there is a minus printed on the Cap - that lead goes to the ground). Place a 100k-200k resistor between pin 1 and 2 of the chip. Then you need to add the series resistor (1-3k) between pin 2 and the LED. Attent to the right direction of the LED. The shorter leg goes to the ground.

I hope you may see it on the image.

If youre done, connect the batty to the plus and minus bus of the breadboard and your first LED should start blinking. :-)

Thats fun! Lets go forward, add more LEDs...

Step 3: Add More Lights

As you can see on the image of the chip (last step) there are 6 inverter circuits on the chip, so what you've done with pin 1 and 2 - you may do with pin 3 and 4, 5 and 6, 8 and 9 and so on... so lets get crazy and add more LED circuits...

You can use every circuit for your blinky thing, so you may have up to 6 blinking LEDs on one chip. Attend to the direction. The first trigger goes from pin 1 to pin 2. On the other side of the chip the direction is mirrored. So it goes for example from pin 9 to 8.

If you do this on a breadboard be careful to avoid shortens between the parts!

Step 4: Get More Control

Our circuit works in the same way the oscillator circuit of Lady Adas Drawdio works. This is descibed over there.

So with the big resistor (100k-200k) you can change the blinking frequency. Place a smaller resistor there, you may see the LED blinks faster. The smaller the resistor, the higher the frequency.  You may also change frequency by changing the capacitor in the same way.

So if you want to have totally control, you may add a potentiometer instead of the resistor. So you can change frequency in realtime ;-).

Step 5: Get Creative

So this is a very easy circuit to make some LEDs blink. You may use it for your chrismas decoration, or simply to have a little light show in your room. Get creative and make your blinking things with it. Would be great to see what youve done with it.

I made this blinky geeky tabletop decoration based on the circuit:

Thanks for reading. Have fun with building!

Participated in the
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4 People Made This Project!


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6 Discussions


3 years ago

IMO, I think you did a GREAT job of it. Well DONE!!



10 years ago on Introduction

Good little circuit. If you wanted to expand it, you could replace the LED with a transistor, and use that to source a few more LEDs (which could be placed in amongst other sets of LEDs operating at different frequencies).

You could also replace the resistor between pins 1 and 2,  with a pair of resistor and diodes in series. You can use this to adjust the mark/space ratio of the oscillation.

          R1      Diode
--|                          |-----
          R2      Diode

Combining these two will allow you to make a more random twinkling pattern for xmas lights.


Reply 10 years ago on Introduction

Thanks for the link. There's a video of that japanese fountain that describes it very handy and simple. But your link of course provides more information.


10 years ago on Introduction

Great project; I've been looking for something like this for some time now... I just have one question: Can you replace the CMOS chip used with a TTL version of the 7414?


Reply 10 years ago on Introduction

I think it would be possible with any CMOS Hex Schmitt Trigger Inverter chip. If you have one just try it out ;-), think you cant destroy something.