Electric Circuits

An electric circuit consists of the various conductors that lead from the negative to the positive terminal of a source of electricity. The various parts of a typical house circuit include a fuse or circuit breaker, wires, switches, wall outlets, and light sockets.

A circuit through which electricity is flowing is said to be closed. A circuit generally contains a load, a device such as a lightbulb or appliance that provides resistance in the circuit.

If a current is allowed to flow from one terminal to another with very little resistance, a short circuit results. With a decrease in resistance there is an increase of current (amps) where wires can heat up and a fire may start. Fuses and circuit breakers protect the wiring from short circuits by blowing or tripping to specified current loads.

There are two basic methods of wiring a circuit: in series and in parallel.

In the series circuit the current flows through one device (such as a lightbulb) to reach the next. Current is the constant. This is not practicle in our homes as the voltage drops occur leaving less voltage for the next load.

In the parallel circuit the current enters and leaves each device separately. Voltage is the constant accross all loads. This is how our house wiring works.

Many electrical applications use a combination of these two types of circuits.