Simple Circuit

 Simple Circuit

A circuit is a complete path along which electricity flows. The essential elements in a basic electrical circuit consist of: A source (battery), load (light bulb),Switch and ground. Electricity cannot flow without a power source (battery), and a load (bulb or resistor-electrical device/ component) and a closed conductive path (wires connecting it). Electrical circuits consist of wires, switches, circuit protection devices, relays, electrical loads, and grounds. The circuit shown above has a power source, switch, a lamp and wires connecting each into a loop. When the connection is complete, current flows from the positive terminal of the battery through the circuit to the negative terminal of the battery.

In a complete circuit, the source voltage supplies the electrical pressure that pushes the current through the circuit. The source side of the circuit includes all parts of the circuit between the positive side battery post and the load. The load is any device in the circuit that produces light, heat, sound or electrical movement when current is flowing. A load always has resistance and consumes voltage only when current is flowing. In the example below, one end of the wire from the second lamp returns current to the battery since it is connected to the vehicle body or frame. The body or frame works as the body ground (meaning that part of the circuit that returns the current to the battery).

Types of Circuits

There Are Two Types Of Circuit

1)Series Circuit

2)Parallel Circuit

Series Circuits

The components of a series circuit are connected end to end one after another to make a simple loop for current to flow through the circuit. A Series Circuit has only one path to ground, all loads are placed in series, so current must go through each component to get back to ground. If there is a break in the circuit (such as a blown light bulb) the whole circuit and any other bulbs go out. If the path is broken, no current flows and no part of the circuit works. Christmas tree lights are a good example; when one light goes out the entire string stops working.

Parallel Circuits

A parallel circuit has more than one path for current flow. The same voltage is applied across each branch. If the load resistance in each branch is the same, the current in each branch will be the same. If the load resistance in each branch is different, the current in each branch will be different. The components of a parallel circuit are connected side by side so the current flow has a choice of paths in the circuit. If one branch is broken, current will continue flowing to the other branches.

In the parallel circuit below, two or more resistances (R1, R2, etc.) are connected in a circuit as follows: one end of each resistance is connected to the positive side of the circuit, and one end is connected to the negative side.