Circuit diagrams

Circuit Diagrams and Components

Diodes

Series and Parallel Circuits

Advantages of connecting resistors in parallel

1. Voltage across each resistor = voltage of mains
2. Appliance can be switched on and off independently.
3. If one appliance goes off, the others stay on.

Potential Divider Circuit

• The potential difference across the resistor is proportional to its resistance.
• In the above example, the bulb and the variable resistance have a maximum resistance of .
• When the slider is at A, the brightness of the bulb will be maximum as the potential difference across it will be maximum.
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• The bulb will light at an intermediate brightness when the slider is at B.
• The bulb will not light when the slider is at C as the potential difference across it will be 0.
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Relay Circuit

• Works like an electric switch
• It has two coils – primary and secondary.
• A small input current in the primary circuit can be used to turn the switch in the secondary circuit.
• Primarily used for appliances of large loads