What Everybody Ought To Know About the 555 Timer

The 555 timer is a chip that we use to get timing into our circuits without using a microcontroller. What can you do with timing, you ask? Lots of things!

It’s pretty cheap and has been around for a long time. Here is what everybody ought to know about it.

NE555 DIP & SOIC.jpg

NE555 DIP & SOIC” by Swift.HgOwn work. Licensed under CC BY-SA 3.0 via Wikimedia Commons.

You Can Make Sound With The 555 Timer

With the 555 timer you can easily make an oscillating signal. An oscillating signal is a voltage that goes up and down regularly. For example between 5 volt and 0 volt. If it goes up and down really fast – you can hook it up to a speaker and you will hear a sound. So you can use it to make an alarm.

You Can Make A Light Blink

Like mentioned above, you can create an oscillating signal. Let’s say we have the same signal as above, just that it switches between 0 and 5 volt a lot slower… Hook this up to a light and you will have a blinking light. This is an alternative to the two simple ways to blink a light.

Turning Something On For a Certain Period Of Time

The 555 timer can be configured so that you when you give it a trigger signal, it gives out an output voltage for a certain period of time. Then you can use this voltage to turn on a motor or a light in an interactive museum installation, and automatically turn it off after a set time.

It’s a Cheap Chip

You can usually get it for less than 50 cent. And you can buy it from Jameco.

The Time Is Set Using Resistors And a Capacitor

The specific timing of the chip is determined by resistors and a capacitor. To find out how to calculate it, check out this page. You can also find a lot of good circuits and more in-depth explanation of how it works there. Definitely worth checking out.

I’ll end this article with a practical example. Here is how you can make a metronome with the 555 timer:

555 timer metronome circuit

Return from “The 555 Timer” to “Electronic Components Online”

Share on social media:

Get a FREE eBook!

...and receive my newsletter with daily tips and tricks on building electronics
Learn to build a doorbell, portable speakers, and other fun circuits with this FREE mini-eBook.


  1. Dan Okrasinski says

    Some years ago when the 555 first became available to hobbyists for a reasonable price I experimented with making them power an ocillator. I used values that made it quite uncomfortable for human ears and other pests/ It was so high jn pitch I used it to drive some raccoons from under my deck. It also caused the neighbor to complain but I only used it for a night or two.
    Time has passed and I have forgot the values I used to make it squeal. Any ideas.

  2. sibusiso says

    Thank you , you are very clear and simple.
    I really enjoyed it.

    Is there a most simple but reliable radio control for model toys? I so desire to know how to make it. (Both the receiver and the transmitter)


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong> <pre lang="" line="" escaped="" cssfile="">