A NE555 tester

In case you should need one. 

This one I found on YouTube a long time ago. I have written down the parts list and had a sketch that told me where things should be going, But it was poorly documented, so I just had to guess and measure a bit to get it together. I would have credited the YouTuber that showed it to me, but I just could not find the film clip, and I searched for quite some time.

The result was not very like the sketch, but the parts-list was fairly OK. It did say that this should be a 12V unit, but with the LEDs I used I made it work best at 3V, which is nice. Easy to get a two battery holder for some AA-batteries, should I need one.

In addition to soldering tin, hot glue and some insulated copper wire, I have used following parts:

  1. Prototype board (5*7 CM)
  2. 8Pin DIP socket
  3. 1µF 50V capacitor
  4. LED 3V
  5. 1 * 5.1KΩ & 2 *1KΩ resistors
    The problem was that I didn't have a 470Ω resitsor at hand, so I went to an online resistor calculator and found out that one 5.1 KΩ ant two 1KΩ resistors in paralell would give me a resistance of 455.36 Ω. That's within 5% ± that can be tolerated.
  6. 10KΩ resistor
  7. 100KΩ resistor
  8. Pins for power in
  9. Feet
    I use screws at the bottom too. It looks better, I think. These are spacers like the ones you'd fasten your motherboard in your desktop with.
  10. A micro switch
    This one was not on the drawing I've drawn before. I just thought it'd be nice with one. That's why it has its own picture here too.

How I put it together

  • First the socket was soldered on about in the middle of my board.
  • The capacitor came next and (-) is placed close to pin 1 on the chip
  • Then I soldered on the bundle of resistors that should replace the 470Ω resistor.
    That turned out to be a mistake as it made it worse for me to connect the backside afterwards.
  • The two other resistors got soldered on - the 10KΩ turned out to be the only one not standing, since I could use less tracing on the backside then.
  • The LED was soldered on, but I didn't cut the (+) wire, so I wouldn't have to connect them the wrong way.
  • Then i soldered the micro switch.
  • And last on the front side, I soldered on the pins for power in.
  • On the back side I soldered the wires according to the schematics I've made - or so I thought.
    When it first wouldn't work, I started troubleshooting and found that I've done three misplaced soldierings that I had to correct.
    I also found that I kept blowing my LED. Now this system was, where I found it, using 12V. Some measuring with a multimeter soon showed me that all the voltage got pushed straight through. Changing to 3V fixed that!
  • When all the soldering was done, I used hot glue to fasten the copper wires on the back, so they wouldn't shake loose or rub each other and make a hole in the insulation varnish.
  • Then, last, I added power instructions on the front together wit a name tag.


Above you can see the wonder both from the front and back. If it looks good on the front side, I just can't say the same about the back. I know I'll manage to make them better with training, and it is a safe, good build, even if it doesn't look to good from beneath. And it works. If the LED bulb is lighting when you press the button, the NE555 -cip is in working order. If not.... well then it isn't!

As always, hope you learned something! 

My next project will be to add captcha and contact form to these pages, so you can contact me if you are wondering on something about the builds.

To learn about what the NE555 do, check out this film clip on YouTube!

The contact form is now active!