Symbols of Electric Components
The various components for generation and use of electric current is listed below.
The above figure shows various electrical components and their symbols used in electric circuit.
- Electric Cell – The longer line represents the positive terminal and the shorter line represents the negative terminal.
- Battery – It is a combination of two or more cells. Observe in the figure that the positive terminal of a cell is connected to the negative terminal of another cell.
- Switch – When the switch is in OFF position, the circuit is not complete hence, the bulb will not glow but when the switch is in ON position, bulb will glow as the circuit is complete.
Heating Effect of Electric Current
Have you ever been cautioned by your parents not to touch a glowing bulb? Can you guess why the bulb gets hot?
It is due to heating effect of electric current.
Using the properties of wires (material, length, thickness), we can use the heating effect of current to our advantage. But there is a maximum safety limit on the amount of current flowing through the circuit and sometimes the heating effect of electric current can cause inconvenience.
Magnetic Effect of Electric Current
In both cases i.e. when a magnet is placed near a magnetic compass and when the electric circuit is placed near a compass, the magnetic needle will deflect from its ideal N-S position.
What can be infer from the above two situations?
The current flowing through the circuit produces a magnetic effect which deflects the magnetic needle. In other words we can say that the current flowing through an electric circuit acts as a magnet.
- Electromagnets are created using the magnetic effect of the current.
- The coil used will behave as an electromagnet till the current passes through it, once the flow of current stops, it loses its magnetism.
- Electromagnets are used to lift very heavy loads.
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