Building Electric Circuits

Understanding Electric Circuits

An electric circuit encompasses a complete loop through which electricity can flow.
The three basic components of a simple electric circuit are a source, a path for the electricity, and a load or device.
The source often is a cell or a battery that provides the electrical energy.
The path is generally a wire that electricity flows through.
A load can be a light bulb, motor, or other device that utilizes the electrical power.

Components of an Electric Circuit

Resistors are used to control the electrical flow or current in the circuit.
A switch can be opened or closed to control the electricity flow, enabling us to turn on/off devices.
Circuits can be connected in two main ways: series and parallel.

Building Circuits in Series and Parallel

In a series circuit, all components are connected end-to-end to form a single path for electricity. The current is the same at all points in a series circuit.
Advantages of series circuits are that they are simple to make and the total voltage is the sum of the voltages across each component.
Disadvantages are that if one component fails, entire circuit stops working, and the more components added, the higher the total resistance goes.
In a parallel circuit, each component has its own separate loop. The voltage is the same across all components, and the total current is the sum of the currents through each component.
Advantages of parallel circuits are that they will still function even if one component fails, and adding additional components does not increase the total resistance.
Disadvantages are they are more complex to design and build and require more wiring.

Understanding Ohm’s Law

Ohm’s law states that the current flowing through a conductor (such as a wire) is directly proportional to the voltage and inversely proportional to the resistance. It is expressed as I = V/R, where I is current, V is voltage, and R is resistance.

The Role of Resistors

Resistors limit the flow of electric current; high resistance results in lower current whereas low resistance results in higher current.
Resistors can protect the components by preventing an excess flow of current which could damage them.
The resistance offered by a resistor can be calculated using Ohm’s Law if the current flowing through the resistor and the voltage across the resistor are known.