4.2 Circuit Boards
4.2.1 Types of Circuit Boards
Correct mechanical and electrical constructions are a prerequisite for electronic circuits. In order to get good mechanical stability electronic circuits are built on boards. Dependent on the purpose of the electronic circuit several kinds of boards are available, such as:
- Soldering strips
- Raster boards
- Tag raster boards
- Veroboards
- Printed circuit boards.
4.2.2 Convetional Circuit boards
4.2.2.1 Soldering Strips
Simple electronic circuits with low voltage supply or battery supply can be built very easily on soldering strips. Soldering strips are no longer used in industrial circuits. For test set -ups or in the field of hobby electronics, however, soldering strips have still been employed.
4.2.2.2 Raster Boards
Raster boards are used for simple electronic circuits. They consist of hard paper without copper coating. The board is perforated with holes 1.3 mm in diameter and in a raster of either 2.54 mm or 5.08 mm. The components are fitted to one side, designated ’component side’. The connections of the components are led through the holes and soldered together on the back side of the component side. The leads of the components or silver -coated wire may be used for the connection of the components.
4.2.2.3 Tag Raster Boards
Raster boards with copper coating around each hole (tag) are designated ’tag raster boards’. The copper coating has a thickness of 35 mm. The diameter of the hole is 1.0 mm to 1.3 mm with a tag diameter of 3 mm. The base material may be hard paper or epoxy resin paper in 1.5 mm thickness.
The components can be fitted to each side of the tag raster board. The leads of the components, silver -coated wire or solder bridges, may be used for the connection. Raster boards are available with different tag rasters, e.g. 2.54 mm or 5.08 mm, and as an additional feature with an integrated plug -in junction.
The advantages of tag raster boards are:
- Test set -ups can be built without preparation in a very short time.
- The circuit and circuit layout can be changed very easily.
- Tag raster boards are reusable.
Mechanical instability and low adhesion of the tags are disadvantages of tag raster boards. Therefore great care must be taken when components are unsoldered from tag raster boards. The components and connections must be removed without excessive force, otherwise the tags may be disconnected from the board.
4.2.2.4 Veroboards
Prototypes and test set -ups of electronic circuitry can be built very easily on Veroboards. Veroboards consist of high -quality hard paper as base material. One side of the base material is coated with straight copper conductor tracks arranged in parallel. The copper tracks are perforated in a defined raster whereby 2.54 mm or 5.08 mm are commonly used. Veroboards are available in different forms.
Advantages of veroboards are:
- Test set-ups can be built without preparation in a very short time.
- The circuit can be changed very easily.
- Veroboards are reusable.
Mechanical instability caused by the perforation of the board and low adhesion of the copper conductors are disadvantages of veroboards. Therefore great care must be taken when the components of the veroboard are unsoldered. The components and connections must be removed without exerting excessive force.
