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Building electronic circuits

There are different ways of creating electronic circuits depending upon tools available and how permaenent a solution is required. When creating a new circuit it is common to first create a prototype using a breadboard or similar before the circuit is made permanent using solder. This allows any problems to be identified at an early stage where it is easier to change the design than removing soldered components.

The final design is normally created onto something more permanent such as a printed circuit board, or strip-board.

Wirewrap / solder pins

A simple circuit can be created by hammering nails into a piece of wood and then wiring / soldering between the pins. This is the way that I created one of my first ever circuits at school whilst studying for my GCSCs. More sophisticated systems using specialist boards and special wire-wrap tools.

This is a good way to build very basic circuits when first starting out in electronic circuits. It is also a good way of teaching as the circuit diagram can even be drawn onto the wood showing the circuit diagram compared with the real components. I would not recommend this technique for more complex circuits and in particular once you start using integrated circuits breadboards are usually much better.

Solderless Breadboards

Electronic triac and optoisolator circuit on breadboard

Solderless breadboards (also known as plugblocks or plugboards) are a good way of creating temporary circuits to allow testing prior to commiting with solder. They consist of a plastic board with a matrix of holes. These are then connected in small rows so that components plugged into the same section are connected together.

Breadboards are very easy to use and don't damage the components. Integrated circuits (ICs) can be easily inserted and wired to other components. Some are also available with mounting frames for potentiometers etc. Solid core wires are needed for connecting to the breadboard (if you normally use the more flexible multi-core wires then you should get some solid core for the breadboard. If you find that you are creating a lot of circuits then it can be easier to buy a box of pre-cut lengths, although these are more expensive than just cutting standard wire to the appropriate length.

The 25 minute electronic training session used solderless breadboards to allow the learners to build a buzzer circuit.

Stripboard

Electronic circuit on stripboard Stripboard or Veroboard (trademark name of company that first invented it) provides a way of creating soldered circuits without the expense and complexity of creating a custom printed circuit board.

It is a board with a 0.1in (2.54mm) grid of holes with strips of copper running in a single direction across each row. Normally these extend the full length of the stripboard, but there are some versions with a break in the copper tracks suitable for mounting integrated circuits.

This is a very common way of creating permanent circuits for hobby electronic enthusiasts who may not have the equipment for creating a complete printed circuit board.

Much of the Computer controlled disco and theatre light project is created using stripboard.

Printed Circuit Board

A printed circuit board (PCB) is the most professional way of creating a completed permanent circuit. Most hobby circuits are created using single layer PCBs, 2-layer can be created using home equipment, but any more requires specialist equipment.

The following process describes how a typical printed circuit board can be made. There are other methods such as - iron and peel transfers to replace the photo etching process.

  1. Track layout is created, either by hand or more commonly on a computer
  2. Track layout is transferred to transparency
  3. Transparency is placed against blank PCB and exposed to UV light
  4. PCB is put into developer to fix the image
  5. PCB is placed in etching liquid (acid) to etch away exposed track
  6. PCB is cleaned
  7. Holes are drilled for component leads
  8. Components are soldered onto the PCB

There is an example of a two layer PCB in the Bike alarm project.

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