Circuit Symbols

Circuit symbols are used in circuit diagrams which show how a circuit is connected together. The actual layout of thecomponents is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing thelayout of the parts on strip board or printed circuit board.Circuit symbols are used in circuit diagrams, which show how a circuit is connected together. The actual layout of thecomponents is usually quite different from the circuit diagram. To build a circuit you need a different diagram showing thelayout of the parts on the printed circuit board. However understanding electronics circuit give you a better understandingof how to find faults in an electronic circuit

Wires and connectionsComponent Circuit Symbol Function of Component

Wire

To conduct or pass current from one part of a circuit to another.Wires joined

A 'blob' should be drawn where wires are connected (joined), but it issometimes omitted. Wires connected to another wire should bestaggered slightly to form two T-junctions, as shown. Such help totransmitted current to other pathsWires not joined

In diagrams it is often necessary to draw wires crossing even thoughthey are not connected. It is preferred to have the 'hump' symbol asshown because the simple crossing of the wire may be misread as a joinwhere you have forgotten to add a 'blob'!

Power SuppliesComponent Circuit Symbol Function of Component

Cell

Supplies electrical energy.The larger terminal indicates the positive (+).A single cell is often interpreted and called a battery, but a battery is two or more cell joined together.Battery

Supplies electrical energy. A battery is more than one cell.The larger terminal is the positive (+). And the small terminal is called thenegative (

-

)DC supply

+ -

Supplies electrical energy.DC = Direct Current, always flowing in one direction.AC supply

Supplies electrical energy.AC = Alternating Current, continually changing direction of it currents it isnegative and then Positive which alternates again.Fuse

A safety device, which will 'blow' or melt if the current flowing through itexceeds a specified value. Used as a protection for electrical circuits.Transformer  Two coils of wire linked by an iron core. Transformers are used to step up(increase) and step down (decrease) AC voltages. Energy is transferredbetween the coils by the magnetic field in the core. There is no electricalconnection between the coils.Earth(Ground) A connection to earth. For many electronic circuits this is the 0V (zero volts)of the power supply, but for mains electricity and some radio circuits it reallymeans the earth. It is also known as ground.

Output Devices: Lamps, Heater, Motor, etc.Component Circuit Symbol Function of Component