Key Points

An electric cell is a portable source of electrical energy. It has two terminals: a positive terminal (+) and a negative terminal (-).

A battery is a combination of two or more electric cells connected together. To make a battery, the positive terminal of one cell is connected to the negative terminal of the next cell.

An electric circuit is a complete and continuous path for electric current to flow. The current conventionally flows from the positive terminal to the negative terminal of the cell.

An incandescent lamp produces light using a thin wire called a filament. When electric current passes through the filament, it gets very hot and glows.

An LED is a lamp with two terminals, a longer wire (positive) and a shorter wire (negative). Unlike an incandescent lamp, an LED allows current to pass through it in only one direction.

An LED glows only when its positive terminal (longer wire) is connected to the positive side of the battery and its negative terminal (shorter wire) to the negative side.

An electric switch is a simple device used to either complete or break an electric circuit. When the switch is in the 'ON' position, the circuit is closed, and when it is 'OFF', the circuit is open.

A closed circuit is a complete path that allows current to flow, causing a lamp to glow. An open circuit has a break in the path, which stops the current from flowing.

Conductors are materials that allow electric current to pass through them easily. Most metals, such as copper, aluminum, and silver, are good electrical conductors.

Insulators are materials that do not allow electric current to pass through them. Examples of insulators include plastic, rubber, wood, and glass.

Electrical wires are made of a conductor (like copper) and are covered with an insulator (like plastic). This insulation protects us from electric shock.

A circuit diagram is a simplified representation of an electric circuit using standard symbols. The symbol for an electric cell uses a long line for the positive terminal and a short, thick line for the negative terminal.

A bulb is considered 'fused' when its filament is broken. A broken filament creates an open circuit, which stops the flow of current and prevents the bulb from glowing.

The human body is a conductor of electricity, so handling electrical appliances carelessly can be very dangerous. Never experiment with the main power supply from wall sockets.