Welcome to the 555 Timer Assembly Instruction!  This simple circuit is very powerful and has a ton of applications.  Let’s get started!

Component Layout

Check to make sure that you have all of the components included in the kit.  Not only will this help you finish the circuit, but it will familiarize you with each component.

For these instructions, a DC jack is used.  However, this component is not necessary to power your circuit and it is not included in kits.

Alright, let’s get started building!

Board Components

Insert the 555 timer IC into the PCB at the position shown in the picture below.  If the leads are too wide to fit, gently squeeze them inward until the IC fits.

The next component to be place is the resistor R1.

The capacitors are placed as shown.  C1 is a non-polarized ceramic capacitor and its orientation doesn’t matter when inserting it into the PCB.  C2 is a polarized electrolytic capacitor and its placement matters.  The longer lead should be inserted into the square through-hole and the shorter lead should be inserted into the circle through-hole.  Also, the gray band on the body  of the capacitor designates which is the negative lead.

My personal preference is to insert multiple components before any soldering takes place.  Make sure your soldering joints are clean before you clip any leads from the capacitors or the resistor.

Wired Components

The remaining components of the 555 Timer circuit are attached to the PCB via wires.  Use longer wires than you need when soldering to the component.  Wire can always be cut;  desoldering short wires and resoldering new wires to the PCB and component is a very frustrating error that can be avoided

Our first wired component is the potentiometer.  Using the picture as a guide, solder three wires to the potentiometer.  As a general rule, the potentiometer’s solder terminals are numbered 1-3 from left to right.  There are corresponding numbers on the PCB to help guide you.

The 9V battery jack is very easy to solder to the board.  The red wire goes to the ‘+’ PCB position and the black wire goes to the ‘-’ position.

If you are not using a DC Jack with your circuit, you will have to use a jumper wire to connect the ‘S’ and ‘C’  DC Jack PCB through-holes.  Use a scrap piece of lead wire (perhaps one from the resistor or capacitors that you already cut) or a short piece of wire.

If you are using a DC jack with your circuit, read on.

Solder three wires to the DC Jack as shown below.  To make the assembly easier, the wires are color coded and correspond to PCB positions for the DC Jack:  green -> ‘C’, red -> ‘S’, blue -> ‘P’.

That’s it, you’re done!  Now it’s time to test the circuit.  If you have an LED, insert it into OUT through-hole, ‘+’ for the longer lead and ‘-’ for the shorter lead.  You don’t need to solder it, but you may have to move it around to get it to connect correctly.

If everything went right, your LED should be blinking.  Use the potentiometer to increase/decrease the blink rate (frequency).

Mods/Applications

If you are new to electronics, you may not fully understand the point of this circuit.  That’s totally OK and we are going to show you what you can do with it.  There’s more to it than just flashing an LED on and off!

The circuit layout is for a 555 timer in astable mode.  Basically, this means that you will have a continuous transition from a high voltage level (determined by and slightly  less than your supply voltage) to 0V at a certain frequency (number of times per second).  In digital circuits, this is known as a clock pulse and is very important for timing or triggering events.  In fact, our 8/10 step sequencer and 16 step sequencer both utilize an astable 555 timer circuit!

For more info, check out this link.  They do a great job of explaining the circuit as well as showing how to calculate frequency and component values.

Controlling a Relay

CV Input

Circuit Bending