Absolute Beginners Guide to a Basic 555 Timer!

This guide will walk through the steps of setting up a clock pulse using a 555 timer in crumb as an absolute beginner! Feel free to refer back to help memorize the steps!

What is a 555 timer?

The 555 timer is a fundamental integrated circuit used in a wide variety of electronic devices. It's purpose is to oscillate a pulse from low to high (0 volts to 5 volts, assuming 5 volts are being used to power the circuit) at a frequency which can be pre-set by the designer by controlling a combination of resistance and capacitance (with external resistors and a capacitor).

Essentially if we wanted to make an LED flicker, we would connect the output from the 555 timer into the leg of the LED and a high or low frequency depends on our chosen resistor and capacitor. In this 555 timer, I will only be using 1 resistor to make it simpler to understand. The higher the resistance value, the lower the frequency (slower oscillation). The lower the resistance value, the higher your frequency (faster oscillation).

Setting up for the 555 Timer

First things first, we need to set up our breadboard. If you are already familiar with this process, feel free to skip to the next section.

We can grab our breadboard and power rails here:

Then insert them like so and line them up:
(make sure that there are two power rails, 3 total pieces at this point. One rail on the top, and one on the bottom, oriented the same way I have them)


Next, we are going to connect our power supply to the power and ground rails on our breadboard. We will do this by simply plugging the positive cable into the red and the negative (ground) cable into the blue:




It should look like this:




Remember that by placing these cables here we have effectively powered and grounded each pin hole on that row. BUT, we still need to power the rails below it as they are currently connected to nothing. Lets bridge the top and bottom like so:

It should look something like this (color won't ever matter) :



And there you have it! We've set up the breadboard as we would for any other circuit. Now, lets start building our timer.

555 Timer Configuration

Now that our breadboard is set up, and our power rails are receiving power (+) and ground (-), we can place our 555 timer on the breadboard. All IC chips must be placed on the gap on the breadboard, otherwise it would cause complications since power runs via columns on the main breadboard piece.

Grab your 555 timer by clicking the Integrated Circuits menu under "Embedded":


Click the 555 timer:



Add it anywhere on your breadboard. You can copy where I put mine if it helps you!




Next, let's give the 555 timer power and ground. To see the pin names we need to go to the right side of our screen and select the box that says "show pins" or, we can Press "P" on our keyboard to show it as well. We'll use wire again to connect our VCC pin and GND pin to + and - respectively.




After we've done that we're going to connect our |RST pin to +. We are doing this because this pin is active low, meaning it will disable the function of the timer if the pin is connected to ground (-) . This can be confusing at first, but as long as you understand that this must be connected to + if it's active low, you will quickly start to get it!





Next, we're going to connect a wire from our threshold pin (THR) to our timer output pin (Q) with a 1000 ohm resistor in between our connecting wires.

Grab the resistor here, notice the menu on the left where you can change its resistance value later:



Then place something like this:





Next we will add a 100 Micro(µ)Farad electrolytic capacitor:



Make sure it is the proper capacitance! I encourage you to mess around with it later to understand the relationship between frequency and capacitance value.




Then place the capacitor with its anode (positive leg, also the first click) in the same column as the THR pin on the timer. Connect its cathode (negative leg, second click) to ground (-) .

I circled where the positive leg goes!




Just like that, you have made a 555 timer oscillate! You can connect an output component to the Q pin to see it in action!

Test with an LED!

We can now test and visualize our clock pulse by placing an LED on the breadboard and connecting it's Anode (+) leg to Q and its Cathode (-) leg to ground.



REMEMBER! LEDs ALWAYS NEED A RESISTOR! In real life, these lights could burn out from too high current if a resistor isn't placed. I used 1000 ohm (aka 1 Kilo-ohm) for this light but anything should do. It will only affect its brightness :)



Lets turn our power source on and see the light flicker!
Click on the interact button or press E on your keyboard



Then flick the switch to the DC power supply!




Notice: The light appears to be flickering quite quickly! Your challenge: edit and update the resistance and capacitance values on the 555 timer's external components we placed to make it flicker to the perfect frequency for your project. Remember more resistance will make it flicker slower!


Hope you learned something from this! Comment down below if you have any questions or if something isn't working i'd be happy to help you out!

[Nittis]

It brings my heart such happiness that I was able to help you!!

[СёкоМакінохара]

Thank you! I am an idiot on physics stuff but I'm now having fun after reading this!

[Xzenergy]

I wish we had more guides like this!

[CodeManDeluxe]

[MikMogus]

This is wonderful, thank you!

[Bludkin]

its not working for me theirs no flickering

[Bludkin]

thank you i was really having trouble with this