Basic 555 Timer LED Flasher Circuit

Introduction: Basic 555 Timer LED Flasher Circuit

From our build night sponsored by Jameco, this is a fairly basic and common 555 LED Flasher Circuit. Component values may be different but the basic function of a 555 IC is as an oscillator.

Required Componenets
  • 1 - 555 Timer IC
  • 2 - 1kohm Resistors
  • 1 - 470kohm Resistor
  • 1 - LED of any color
  • Several Different Capacitors
  • 9VDC Battery
  • 9VDC Battery Adapter
  • Small Breadboard
  • Breadboard Jumpers

Step 1: Breadboarding

If you've never used a bread board before it may be a bit confusing. I'll start by explaining the electrical connections in a breadboard.
This particular breadboard has 3 sections, two of which are the same.
Breadboards are perfect for prototyping and its not uncommon to have them house projects permanently. 

The sections on the left and right of this breadboard consists of two vertical columns that are connected electrically. Place a component at the very top, near the red stripe and place another component at the very bottom near the red stripe and you will have electrical connectivity. The same goes for the row nearest the blue stripe.

The center section of the bread can be considered the Main section. The numbered rows consist of 5 perforations that are connected electrically. The Lettered columns are not connected electrically. So for Row #5 holes A, B, C, D and E are all connected electrically. The same for Row #5 holes F, G, H, I and J. The distance between each set of columns perfectly fits several ICs. Most importantly, our 555 Timer IC.

After examining the schematic began placing components onto the breadboard. It might help to start with the 555 Timer IC since it is the most crucial part of this project.

You'll notice that you cannot make some connections by using the breadboard alone. For instance, I used the side sections for my Positive and Negative connections. I connected these with jumper wires.

Step 2: Experimenting!

You'll notice the big brown capacitor I used for this circuit. This was chosen at random as it produced a nice steady flash on the LED. I encourage you to swap components out for different valued components and observe the results. 

Different capacitors either sped up, or slowed down, the flashing of the LED.
Different resistors will also have other effects on this circuit.

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    7 years ago on Introduction

    Your diagram shows pin 3 going through a LED to Vcc instead of GND.


    Reply 7 years ago on Introduction

    I might add that the 555 sinks more current than sources current, else the 555 does a better job of switching to ground than to Vcc


    7 years ago on Introduction

    Eliminating the bypass capacitor from pin 5 saves you parts count

    Alas if you eliminate pin 7 and use pin 3 instead you could have eliminated a resistor and gives you 50% duty cycle also.

    Gr8 instructable merci beaucoupe for sharing

    this is n8zu in 8 land