Irby Electronics

Irby Electronics

Colours

Twist the free ends of the cables attached to S1 around the terminal pins at A21 and A23 and solder them together. Make sure that a stray wire or excess solder does not bridge the gap between the two terminal pins.

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

17.     Assembly is now complete. Carefully compare your circuit with the wiring diagram and the pictures above. Check, again, that there are no solder splashes across adjacent tracks and that the tracks are completely broken in the correct positions (there should be a total of 5 track breaks on the track surface).

Connect a new PP3 9 volt battery to the battery clip and switch on.

Enjoy!

  • 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.

6.      Identify resistor R3 with bands of red, red and orange. Bend the leads of R3 so that they can be pushed through holes A14 and F14. Spread the ends of the leads slightly apart and carefully solder. Trim excess wire from the leads of R3.

7.      Push the positive lead of the second l.e.d. through A17 and the negative lead through B17. Spread the ends of the leads slightly apart and carefully solder. Trim excess wire from the leads of the l.e.d.

8.      Identify the three leads of TR2 (refer to earlier picture). Bend the leads so that the emitter lead fits through hole
I17, the base lead fits through H18 and the collector lead fits through G17. Spread the ends of the leads of TR2 slightly apart and carefully solder. Trim excess wire from the leads of TR2.

9.      Push the positive lead of the second capacitor through G20 and the negative lead through F20. Spread the ends of the leads of C2 slightly apart and carefully solder. Trim excess wire from the leads of C2.

10.     Resistor R4 has bands of yellow, violet and brown. Bend the leads of R4 so that they can be pushed through holes B24 and G24. Spread the ends of the leads slightly apart and carefully solder. Trim excess wire from the leads of R4.

11.     Push terminal pins from the track surface through to the top surface in positions A25,
I25, A21 and A23. Terminal pins are a tight fit and pliers are usually needed to squeeze them through the holes. (Terminal pins have a habit of jumping off the table and are never found again - two spare terminal pins are provided in the kit.)

12.     Make a track break position A22 before attempting to solder the terminal pins. A copper track can be broken by carefully scraping the copper away with a sharp craft knife or, more easily, by pressing a 3 mm drill bit (not supplied in this kit) into a hole on the track surface and gently twisting the drill until all of the copper track at that position has been removed.

Solder the four terminal pins to the track surface. The pictures below shoe the track break and terminal pins on track A before and after soldering:

Think  SAFETY.   Act  SAFELY.

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

close-up of track

break at A22 and

soldered terminal pins

close-up of track surface

showing soldered joints

switch S1 and

cable connections

close-up of track

break at A22 and

terminal pins

before soldering

Push the positive lead through G7 and the negative lead through F7. Spread the ends of the leads of C1 slightly apart and carefully solder. Trim excess wire from the leads of C1.

4.      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 hole A7 and the negative lead through hole B7. 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.

5.      Identify resistor R2 with bands of red, red and orange. Bend the leads of R2 so that they can be pushed through holes A10 and F10. Spread the ends of the leads slightly apart and carefully solder. Trim excess wire from the leads of R2. The pictures below show this stage of construction:

close-up of top

surface showing D1, R1,

R2, C1 and TR1

1.      Identify resistor R1 which has bands of yellow, violet and brown. It does not matter which way around a resistor is connected in a circuit. Bend the leads of R1 so that they can be pushed through holes B2 and G2. Spread the ends of the leads slightly apart and carefully solder. Trim excess wire from the leads of R1 using wire cutters.

2.      It is essential that the transistor, TR1, is correctly connected to the other components. Identify the three leads of TR1. The emitter lead is nearest to the tag on the metal canister of the transistor. The base lead and the collector lead are also shown in the picture below:

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 two light-emitting diodes which flash alternately on and off at a constant rate. The circuit diagram is shown below.

This construction uses transistors TR1 and TR2 to alternately switch on and off the light‑emitting diodes D1 and D2. The rate of flashing depends on the values of resistors R2 and R3 and capacitors C1 and C2.

Resistors R1 and R4 are connected to l.e.d.s D1 and D2 to reduce the amount of current flowing through them. Too much current can cause an l.e.d. to burn out.

This project requires one PP3 battery (not supplied in this kit). In a test of this circuit, a Duracell Plus Power battery was still producing a good output of light after 40 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
  • 3 mm drill bit or sharp craft knife for breaking copper tracks.


Assembly Instructions for Project 12: Alternately Flashing L.E.D.s Using Transistors
Please refer to the wiring diagram and read through these instructions very carefully before starting assembly.

PROJECT 12:   ALTERNATELY FLASHING L.E.D.S USING TRANSISTORS

negative lead of a capacitor

13.     Break the copper tracks at B12, F12, G12 and H12 to isolate components in the two halves of the circuit.

14.     Take one of the insulated wire links and push the ends through the top surface into holes F11 and H14. Bend the ends of the wire link slightly apart and carefully solder.

Take the second insulated wire link, push it through holes H10 and F15 and carefully solder. Trim excess wire from the links using wire cutters.

15.     Identify the two cables for the slide switch, S1. Push the end of one of the cables through the hole in the central tag of the switch, gently twist together and solder. Push the end of the second cable through the hole of either one of the remaining tags, twist and solder. Make sure that solder does not bridge the gap between these two connections on the switch. (The third tag on the switch is left unconnected.) Your switch should now look like that shown in the picture below:

close-up of leads of transistor TR1

Bend the leads so that the emitter lead fits through hole I4, the base lead fits through H5 and the collector lead fits through G4. Spread the ends of the leads of TR1 slightly apart and carefully solder. Trim excess wire from the leads of TR1.

3.      Identify capacitor C1. This type of capacitor has a positive lead and a negative lead. The negative lead is marked with a minus sign on the side of the canister as shown: