We use many electric appliances in our daily routine. But have you ever thought upon its internal system, how it is joined so that it should work properly. Just consider the simple electric device ‘torch’. If your teacher provides you all the components required for making torch like cell, switch, wires and small bulb, can you connect them in proper pattern? If yes then you have connected nothing but the electric circuit. Take a look at the figures below.
In first figure electric devices are shown before connecting, whereas in second figure all devices are connected in proper way such that as we tap key, current will start flow in the arrangement and bulb will glow. Such arrangement is called as electric circuit, and representation of such circuit with the help of diagram called as electric circuit diagram.
Electric circuit is then defined as the arrangement of several electric components in such a manner that it forms a close network through which current flows continuously. The representation of such network with diagram is known as electric circuit diagram. Shown in fig.2. But every time when we wish to draw circuit diagram as above, it’s difficult and time consuming to represent the components as it is, so that the most convenient way is to draw symbols instead of drawing exact picture of the given component. The representation of electric circuit with symbols for the components in closed loop is then called as Electric circuit diagram. Refer the diagram shown below, which is alternative for fig. 2 shown above.
In the diagram cell, key, bulb and wires are shown with their symbols. Straight lines in red colour are used to show connecting wires. Arrows are used to indicate the direction of flow of current. This is very convenient method to study electric circuit.
For remote control of TV set you must have seen more than one cell. How are they connected ? Most of the times in electric circuit we need more than two cells for more amount of current. Two or more cell to combines forms battery. In such a type of combination negative terminal of first cell is connected to positive terminal of second cell and so on.
ELECTRIC COMPONENTS AND THEIR SYMBOLS
Go through the following chart to learn the symbols used for different electric component.
Battery |
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Plug key |
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Tap Key |
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Resistor |
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Variable resistor |
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Voltmeter |
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Ammeter |
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Bulb |