Assemble a Household Circuit
Aim
To assemble a household circuit comprising three bulbs, three (on/off) switches, a fuse and a power source.
Apparatus and Material Required
Three bulbs (12 W, 220 V each), three (on/off) switches, socket, a fuse of 1.0 A, plug, flexible connecting wire, main switch.
Principle
If \(P_1\), \(P_2\), \(P_3\), \(P_4\), \(P_5\), … \(P_n\) be the power consumed by different domestic electrical appliances in a circuit then the total power consumption, P at any instant is given by
\[P = P_1+ P_2+ P_3+ P_4+ P_5+ …P_n\]
If electric potential is \(V\), then current \(I\) drawn from the mains is given by \[I =\frac{P}{V}\]
where \(P\) is in watt, \(V\) in volt and \(I\) in ampere.
A fuse with a rating slightly higher (10 to 20 percent more) than the normal current used by the appliances is connected in series to protect them. It prevents damage if too much current flows accidentally, such as when the appliance’s terminals are mistakenly connected.
Procedure
- Take the bulbs \(B_1\), \(B_2\), \(B_3\) and connect them in series with switches \(S_1\), \(S_2\) and \(S_3\) respectively. Connect \(B_1\), \(B_2\), and \(B_3\) alongwith \(S_1\), \(S_2\) and \(S_3\) in parallel with each other as shown in the circuit diagram.
- Connect the fuse \(F\) in series with the setup, placing it between the live terminal and the load.
- Connect a plug at the end of two leads. Connect a wire from the earth pin of the plug. The plug is meant to be connected with mains supply.
- Connect a socket as shown in the diagram.
- Press the switches \(S_1\), \(S_2\) and \(S_3\) one by one and observe the bulb that is switched on and off independently of the other bulb.
- Press all the switches simultaneously and observe what happens. Record your observations.
Results
Household circuit assembly is complete and installed with safety.
Precautions
- Care should be taken while working with mains.
- Carefully determine the rating of the fuse by calculating the maximum current drawn by the circuit.
Discussion
Fuse is a safety device. Never use fuse of much higher rating than the recommended value.
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