Electronics Made Easy - a Complete Introduction to Electronics - Martin Denny [19]
Veroboard is generally the cheaper of the two options but is more difficult to use as the parallel tracks must be cut using a track cutter or 3mm drill to form the circuit and the close proximity of adjacent tracks requires great care when soldering components on the board. Additional connections can be made using solid insulated wire. Connections to and from the board should be made with multi stranded insulated wire (7/0.2 or 16/0.2).
Prototype (matrix) boards are also available with no copper tracks. Components can be assembled using a combination of soldering and wire wrap techniques. Wire wrapping involves tightly wrapping wire around a square section conductor relying wholly on mechanical grip for the electrical connection. This technique allows the faster assembly of the prototype but is expensive and unreliable.
3.0 Soldering and Assembly Techniques
3.1 Preparation
There is a natural tendency once you have assembled all the components to rush into building the circuit, but to be successful care should be taken in your preparations.
The first stage should be to measure all the components and their lead spacing (see the next section). It might seem overly pedantic but work in imperial units most components and all of the prototype boards are designed that way and multiples of 0.1 inches are easier to read than 2.54mm.
Using different colour pens draw the circuit layout including component dimensions. It may help to use squared paper or graph paper.
Example of a Simple Layout on a 0.1 inch Grid
When drawing a layout especially for high frequency circuits keep the connections as short as possible. Remember long parallel leads can provide an unwanted path to an adjacent circuit due to capacitance. Oscillators especially can provide high frequency noise to the rest of the circuit.
A small polyester or ceramic capacitor (say 0.1uF to 1uF) connected across the power feed ie V to 0v, as close as possible to the source of the noise should considerably reduce the problem, so make allowances in the layout drawing.
When the drawing is complete check it carefully against the circuit diagram as from now on mistakes can be expensive both in time and money. Please always retain you layout drawings as if anything goes wrong they will be needed.
3.2 Assembly
Most components can be horizontally or vertically mounted on the board but unless space is at a premium it is generally better to mount horizontally.
When preparing passive components and diodes for mounting grip the component lead close to the body using small long nosed pliers and bend the remaining part of the lead as required.
It is better to assemble a reasonable number of components before soldering therefore when the component is in position bend the leads on the underside of the board slightly to retain the component.
When positioning integrated circuit bases it is better to position the base then solder two pins to the board while holding the base. Later when soldering the whole base solder the two original pins properly. Remember pin 1 is marked or a semicircle is cut in the moulding at the top of the base. I prefer to position all the bases first without other components to get in the way.
Don’t try to save money by soldering integrated circuits directly to the board, they can be easily damaged and you may need to remove them when testing the board on completion of the project. Turned pin DIL sockets are generally the most reliable.
Turned Pin Dual In Line Sockets
Most discrete semiconductors ie diodes and particularly transistors are vulnerable to heat therefore additional care must be taken when soldering. Whenever possible solder these components last and allow the component to cool after each joint. If the semiconductor is to be soldered to a large area of track or tag, soldering time will be increased, and it