Circuit is the essential element in any electrical or electronic system.Circuit is the pathway that electricity takes electrical current. It is also a closed loop that electrons can flow. Before electrons will flow, however, it must have a complete circuit. A complete circuit is a circuit through which an electron (current) can flow.
A complete circuit usually consists of three parts:
• Power or energy source-This pushes the electrons through a circuit. For example, a battery.
• A connection- This is a material that allows electrons (current) to pass through it. For example Aluminum, copper and so on.
• A load- This is the part that uses the electricity. A load can be a radio, bulb, TV, Fridge and so on.
For electrons to flow constantly, a circuit must not have any breaks in it.
There are three types of circuits which are open, close and short circuit.
• Open circuit– This is a circuit where the flow of current has been interrupted or broken. Generally, any circuit that is incomplete is known as an open circuit. Open circuit can be intentional or un-intentional. It is intentional through the usage of switch to turn off lights in a room. It is un-intentional when a circuit breaker or fuse blows due to excess current on the circuit.
• Close circuit-This is a circuit where is continuous flow of current without interruption. A close circuit is a complete circuit.
• Short circuit– This is the direct connection between positive and negative of a power source i.e. it is simply a close circuit without a load in it. It is also a circuit where is low resistance connection between two conductors supplying electrical power to a circuit.
Short circuit can result to fire or explosion. A common example of short circuit is when the positive and negative terminals of a battery are connected with a wire. This makes the cell to deliver large amount of current in a very short time which in turn results to quick buildup of heat and explosion (the release of hydrogen gas and electrolyte which can burn tissues or cause blindness).
Overloaded wires can also cause short circuit. A wire overheat when it’s overloaded, causing damage to the wire’s insulation which bridges the neutral and the live wires together, thereby resulting to short circuit. If the power source is not interrupted, this can result to fire outbreak. That is why fuses and circuit breakers are used in electrical wiring.