Printed Circuit Boards - Introduction

PCB Electronic circuits in schools and industry are normally manufactured through the use of PCBs (Printed Circuit Boards). The boards are made from glass reinforced plastic with copper tracks in the place of wires. Components are fixed in position by drilling holes through the board, locating the components and then soldering them in place. The copper tracks link the components together forming a circuit.    The two diagrams below show the track side of a PCB (normally the underneath side) and the component side (normally the top side) of the same circuit. The relay and integrated circuit are ready to be placed in position and soldered.
	A circuit such as the one shown opposite can be drawn using software such as ‘Crocodile Technology®’ (now known as Yenka Electronics). This allows individual components such as resistors, integrated circuits and capacitors to be dragged onto the screen and connected together, forming a complete circuit. The finished circuit can then be simulated on screen. If the circuit is not correct it can be altered until it works in the desired way. This allows you to test the circuit on the computer and correct any mistakes or make improvements. This saves time as there is no need to build the circuit with real components.
	Circuits can also be built on a breadboard using real components. This is a time consuming method and often mistakes occur as many components are small and it is easy to connect components incorrectly, causing a circuit to fail. Also, breadboards are prone to damage as the small connections on the boards are quite delicate. Using simulation software such as Crocodile Technology® is recommended as it is a much more reliable and accurate method of testing a circuit.