Conductor Insulator Current Measuring Current Voltage Measuring Voltage
An electric current is a flow of charge Electrons carry the charge Metals are good conductors as more free electrons are present and electrons can move easily. Electrons cannot move easily in insulators.
Some electron in a metal will flow when a voltage is applied.
The rate of flow of charge is called an electric current. Current = Charge / Time I = Q/t Unit: Ampere (A) It is measured by Ammeter. Ammeter has very low resistance. It is connected in series in a circuit.
Voltage is work done per unit charge to transfer the charge across any point in a circuit. Unit: Volt (V) It is measured by Voltmeter Voltmeter has high resistance It is connected in parallel to a device.
A circuit have power supply (cell/battery), switch, any device and connecting wires. Switch closed = ON, switch open = OFF
A circuit with single loop where current can flow in only one path is called series circuit. The following picture shows the series circuit:
Advantages: Less wire is needed. Single switch can operate all devices. Disadvantages: If one bulb breaks all other bulb will go off. As voltage is shared more the bulb added more the dimmer they all become. Examples: Decorative lights.
A circuit with multiple loop where current can flow in more than one path is called parallel circuit. The following picture shows the series circuit:
Advantages: Each device can be operated individually. If one bulb breaks other works normally. All device can work with full power or all bulb can work with full brightness. Disadvantages: More wire is needed. Example: Household connections.