Circuit Diagrams

Electric circuits are constructed using components such as batteries, switches, resistors, capacitors, transistors, interconnecting wires, etc. To represent these circuits on paper, diagrams are used.

There are three types of circuit diagrams:

1. Block diagrams
2.  Schematic diagrams
3.  Pictorials

Block Diagrams:

Block diagrams describe a circuit or system in simplified form. The overall problem is broken into blocks, each representing a portion of the system or circuit. Blocks are labelled to indicate what they do or what they contain, then interconnected to show their relationship to each other. General signal flow is usually from left to right and top to bottom. In fig 2.1 a block diagram is shown represents an audio amplifier

Working of audio amplifier:

Sound is picked up by the microphone, converted to an electrical signal, amplified by a pair of amplifiers, then output to the speaker, where it is converted back to sound. A power supply energizes the system. The advantage of a block diagram is that it gives you the overall picture and helps you understand the general nature of a problem. However, it does not provide detail.

Fig.2.1(An example block diagram. Pictured is a simplified representation of an
audio amplification system.) 

 Pictorial Diagrams:

Pictorial diagrams are one of the types of diagrams that provide detail. They help you visualize circuits and their operation by showing components as they actually appear. For example, the circuit of Fig 2.2 consists of a battery, a switch, and an electric lamp, all interconnected by wire. Operation is easy visualize—when the switch is closed, the battery causes current in the circuit, which lights the lamp. The battery is referred to as the source and the lamp as the load.

  

Fig.2.2(A pictorial diagram. The battery is referred to as a source while the lamp
is referred to as a load.)

 Schematic diagrams:

Schematic diagrams get around this by using simplified, standard symbols to represent components.

Fig.2.3 shows an example of Schematic diagrams. In this, a battery, switch and resistor symbols are used.

Fig.2.3(Schematic