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Design & Technology


Computer-aided design (CAD)

When a circuit has been finalised, a printed circuit board is usually designed and manufactured. Specialist software can be used to plan where the tracks, pads, strain holes and mounting holes will be on the PCB [PCB: Printed Circuit Board ].

The diagram below shows a PCB which has been designed using CAD.

A circuit board has several features: strain holes, tracks, through hole pads, mounting holes and reverse text.

CAD software can also be used to design the structure or housing of control systems. Software can also be used for writing the program used in microcontrollers. It is written in programme-editing software before being downloaded onto the chip.

Advantages and disadvantages of using CAD


  • Can be more accurate than hand-drawn designs - it reduces human error.
  • You can save and edit ideas, which makes it easier and cheaper to modify your design as you go along.
  • You can modify existing ideas, which saves time.


  • The software itself can be expensive so initial costs are high. There are free software packages though.
  • Staff need to be trained how to use the software, which also adds to costs.
  • Requires a PC.

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