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Build Your Own 555 Timer

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The 555 timer. A chip so versatile that it has been used in everything from toys to spacecraft. A chip that can act as an oscillator, a schmitt trigger, PWM driver, a siren/alarm, a light or dark detector, and much much more. It is the most popular IC of all time having been around since 1971 and now selling over 1 billion annually.

This instructable will show you how to build your own 555 timer using only transistors and resistors, no ICs!

Why build this?
Good question.  There are a few different reasons:
1. To Learn:
Learning may be a scary thought to some people, but this project has taught me a lot about comparators and analog circuits as well as a lot of the basics of the 555 timer. The 555 timer combines both digital and analog circuitry  and while digital circuitry is taking over, analog is still important.
2. To Understand:
The 555 timer is a very versatile and useful chip. That's why it is the number 1 most produced chip. It is used very often so it is important to understand how the thing works. Now, you can read about it or even see a simulation, but nothing it quite as good as actually making it yourself.
3. It's Fun:
If you like working with electronics, especially breadboarded electronics, this should be a fun little project. You will break the black plastic barrier that stands between you and your integrated circuits and see the circuit in all its glory (well almost, making your own transistor could be difficult)!

Now that I've hopefully convinced you somewhere within that intro, lets get started!
 
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Lee7315 days ago

That is awesome. Certainly the best how-to I've seen on here....

bigboom3783 months ago
i was wondering what the capacitor on the pcb version was for, stabilising power supply?
Teslaling (author)  bigboom3783 months ago
Yes, exactly.The 555 is notorious for being very noisy, especially when the output changes. I threw the capacitor on it because there was room for it and so I didn't forget during testing. I must not have mentioned it anywhere in the instructable.
thanks for the help :)
sbálint6 months ago
Hi! great work. I'm kind of new to electronics and started to experiment with building oscillators with the 555. my question is would an oscillator (for a synth) sound better with a discrete 555? Thank you!
Teslaling (author)  sbálint3 months ago
It would make no real difference. The discrete 555 and an IC function the exact same way so it wouldn't matter. You would be better off using an IC because they are cheaper, easier to use, and don't take an hour of soldering to be ready to use.
The nerdling8 months ago
should make an atari punk console all on one board without any ICs
Nice work,try make Core2Duo Procesor :-) !
Teslaling (author)  ondrikczech1 year ago
Hahaha!!! That would be nearly impossible!!!
it'd make a very interesting project, it'd only take up half a room, though if you do it right you could overclock it to massive degrees.
Nah, do and Xeon or an i7. Get some speed goin :)
How about an ATmega128p (Arduino)
yes!!!!! do the atmega then make an arduino board around it
bloc978 months ago
Wow great tutorial!
This can show how IC's are all actually simple electronic circuits compressed together.
robot7971 year ago
no do this with tubes :P
Teslaling (author)  robot7971 year ago
Challenge Accepted!
i look forward to the result and i am even willing to supply triode tubes
Teslaling (author)  robot7971 year ago
The first thing I have to do is figure out how some of the elements can be implemented using tubes and how they would connect together. Actually building some circuits wouldn't be for a while but if you would be interested in supplying some triodes, I only have a few on hand and I know that I will need more. This should be a very cool project. I haven't worked with VTs other than with a guitar pedal.
well send me a pm and we will arange is so that the rest to happen
spikec1 year ago
Nice job, you are not only very clever but a great teacher. Thanks!
Thank you very much dude, i really appreciate it. You helped me to finish a school work and i also understood how a ne555 works.
Looking at your board vs. the chip... ICs are the only reason our computers aren't still the size of a barn....
Teslaling (author)  astroboy9071 year ago
Exactly! What is really amazing is that the 555 IC only has about 25 transistors in it. A 8 pin PIC or AVR has several hundred thousand to a few million in the same exact package!
I'm sure due to manufacturing constraints there is an upper physical limit to just how many components can be put on a die in a particular package but in practice there is very little relationship between the two characteristics. Something the examples you cited point out clearly. What is amazing about the 555, that you failed to mention, is that such a simple device has been so popular for so long.

What is more amazing is that many of the tasks the more complex micro-controllers are put to today could easily be accomplished using things as simple as the 555 is.
It does get smaller every year pretty much... We are fitting some 3 Billion transistors into a processor now (thats just average), but with Haswell and intel going down to 5nm production (hopefully by 2015!), we will see massive speed increases...
5nm by 2015 is pretty optimistic. There are physical limitations they've run up against at 22nm. Being as less than 22nm is shorter than the wavelength of light they use with masks to process dies. There are interference games they can play to get a little under that but I don't think the technique can be extended very far. I've heard of some 18nm stuff perhaps that is as low as they can go? The way the industry has been going lately I wouldn't hold my breath for any massive speed increases either. First off no one needs it, second there is no competition on the high end anymore to drive it.

The way forward seems to be parallelization, multicores and clustering. Maybe teaching kids how to program again.
If you are referring to historical computers then you should compare them to their peers now, which are physically large systems. The most powerful supercomputer today takes up 3,000 square feet of floor space, which is a square almost 55 feet on a side. Which is almost twice the physical size of ENIAC which was dubbed by the press a "Gigantic Brain".

Back then there really were no "our" computers so your comparison is basically flawed in that respect.
nodoubtman1 year ago
woww man! :) congradulation! :)
AWESOME! So AWESOME! This is THE best ever 555 timer instructable!
jptrsn1 year ago
Really great instructable! I love building analog circuits from salvaged parts, and this project is right up my alley. You've done a fantastic job of breaking a complex subject into smaller more understandable components. Really well done.
Teslaling (author)  jptrsn1 year ago
Thanks!!! Digital has all but taken over electronics so I've been going analog!

I've been practicing breaking complex things down for a while now! None of my friends can bear more than 5 minutes of me talking about electronics unless I speak to them like they are 6 and my dad is a chemist so trying to communicate what I'm doing involves lots and lots of simplifying!

ynze1 year ago
FANTASTIC! I love this kind of projects!!! I'll never actually build my own 555 timer (I'd rather buy one for almost nothing :-)), but I salute you for taking the time and effort to actually DO this!

Thanks for making me smile!

Y.
Teslaling (author)  ynze1 year ago
Yeah, its much easier and cheaper to buy one than build it and quite honestly, I just wanted to see if it could be done!
pfred2 ynze1 year ago
Yeah I already knew that buying ICs is the best way to go. It is amazing just how much goodness they manage to pack into each one. At one time the 555 was the largest selling chip in history. I'm not sure if that is still true or not, but I wouldn't be surprised if it was. There is no way I'd ever build a 555 from discrete components. I've seen them for sale for like a nickel a piece.
nibrobb1 year ago
You deserve a medal. You have gone really in-depth on this topic and you have written a lot. Really good pictures and very "goodly" explained. Thank you, I'll go order all the components now.(probably not right now; but in the near future).
Teslaling (author)  nibrobb1 year ago
Thanks! Tearing things down like this is something that I enjoy very much. I delve down very far into this project to fully understand everything I could about the workings of the timer so I took the time to share all that I could with the world!

Good luck to you if you give it a go! I would like to see pictures!
Topcat20211 year ago
Amazing job you have done recreating a 555 timer. I love your detail and explanations in the instructable you have made, this should be part of any high school or community college electronics class, for its value in explaining theory,practical application, and trouble shooting circuits.
Keep up the good work.
Dan
WWC1 year ago
WOW
I applaud you for making this and your efforts. I have thought about this several times but just never could talk myself into it because there is many connections and many things could go wrong, but my hat is off to you!

W
LOL you dead a grate job
nice work! this is really well documented.
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