3.1.1 Block Diagram

All electronic equipments can be considered as systems comprising a set of interacting elements responding to inputs to produce outputs. It is quite possible that a system may be too complex to be analysed in detail. It is therefore, necessary to divide it into sub-systems and then integrate them. Each sub-system would then represent a functional block, and the combination of all the blocks would constitute the functional 'Block Diagram' of the equipment. A block is only a 'black box' with certain inputs and outputs, but performing a definite function. The lines interconnecting these blocks indicate the signal flow from block to block or circuit to circuit. Understanding of the circuit function becomes easy with a block diagram. Figure 3.1 shows a typical block diagram representation of a simple recorder.

Figure 3.1: Concept of a block diagram. It shows various sub-systems in an equipment

The integrated circuits such as microprocessors, counters, etc. are represented as individual blocks. These blocks are labelled with pin numbers, signals and associated interconnecting wires.

3.1.2 Schematic Diagram

A schematic diagram is a graphical representation of interconnections of various electronic, electrical and electromechanical components of an equipment. The schematic is the first step in an electronic circuit design because it displays and identifies the components that make up the equipment. Further, the first step in designing a printed circuit is to convert the schematic diagram in to an art master. Therefore, for any printed circuit designer, it is...