3.      Carefully solder the remaining l.e.d.s into positions H8 and I8, A11 and B11, H14 and I14, and, finally, D15 and E15. Trim excess wire from the leads of the l.e.d.s.

4.      Cut, bend and solder wire links into positions A18 and D18, D20 and H20. Trim excess wire from the wire links. These two wire links will connect all of the positive leads of the l.e.d.s together.

5.      Push a terminal pin from the track surface through to the top surface in position A25 and solder on the track surface. The terminal pin is a tight fit and pliers are usually needed to squeeze it through the hole. Push another terminal pin through position
I25 and solder it. (Terminal pins have a habit of jumping off the table and are never found again – two spare terminal pins are provided in the kit.)

6.      Twist the red lead from the battery box around the terminal pin in position A25 and solder them together. Twist the black lead from the battery box around the terminal pin in position
I25 and solder them together.

7.      Assembly is now complete. Carefully compare your circuit with the wiring diagram and the pictures above. Correctly place two new AA batteries into the battery box and switch on.


  • If your circuit doesn’t work and the batteries become hot then you have made a short‑circuit. This is a potential fire hazard! Switch off immediately, remove the batteries and check your circuit to find the problem before continuing.
  • If the problem isn’t a short‑circuit, please recheck your soldering and your batteries.

In this circuit, a resistor is not needed to reduce the current flowing through the light‑emitting diodes. All of the positive leads of the l.e.d.s are connected to the positive side of the battery. All of the negative leads of the l.e.d.s are connected to the negative side of the battery. This is an example of a circuit where the components are connected “in parallel”.

The five l.e.d.s flash independently at slightly different rates to produce a sparkling display. Unfortunately, it is not possible to alter the rate at which the l.e.d.s flash.

This project requires two AA batteries (not supplied in this kit). In a test of this circuit, a set of Duracell Plus Power batteries was still producing a good output of light after 90 hours of continuous use.

To construct this project you will need to use the following tools (not supplied):

  • small, low power soldering iron, e.g. 15 watt, 18 watt or 25 watt
  • small pliers for bending component leads and link wire
  • small wire cutters for cutting component leads and link wire.

Assembly Instructions for Project 10: Sparkling L.E.D. Pentagon
Please refer to the wiring diagram and read through these instructions very carefully before starting assembly.

close-up of top surface

showing soldered joints

example of a

link wire "staple"

2.      Choose one of the l.e.d.s and identify its positive and negative leads. A light-emitting diode will not work if it is connected the wrong way around and so correct identification of the leads is important! Push the positive lead through D7 and the negative lead through E7. Spread the ends of the leads slightly apart and carefully solder. Avoid solder splashing across the copper tracks where you have soldered the l.e.d. Trim excess wire from the leads of the l.e.d. using wire cutters. The pictures below show this stage of construction:

Skill level:      * * *           ADVANCED
Project constructed on track board.
Precision soldering required to avoid solder on one copper track coming into contact with an adjacent copper track.

This circuit contains five light-emitting diodes arranged in the shape of a pentagon. The circuit diagram is shown below. The same circuit is used in Projects 2 and 3 but these projects are constructed on a base of foam board.

Think  SAFETY.   Act  SAFELY.

You're important . . . so also read through the safety guidance sheet provided with the kit.


Irby Electronics


1.      Cut a piece of link wire and, using pliers, bend it to form a shape like a staple, as shown below. Push this staple through the top surface into holes B2 and E2 and bend the ends of the wire link slightly apart. Solder the wire link to the track surface. Take another piece of link wire, push it through holes E4 and I4 and solder. Trim excess wire from the wire links using wire cutters. These two wire links will connect all of the negative leads of the l.e.d.s together.

Irby Electronics

close-up of top surface

showing two wire links

and one l.e.d.