Circuit diagrams and components IGCSE CIE PHYSIC

cell

Supplies the electrical energy to the circuit

battery

A battery is more than one cell.

Power Supply d.c. and a.c.

A power supply is a device that converts one voltage to another more convenient voltage while delivering power.

Ammeter

Instrument used to measure electrical current.

Voltmeter

Instrument used to measure potential dierence.

Lamp

Converts electrical energy to light.

Fixed Resistor

Restricts the ow of electrical current. Can be used to limit the ow of current to a particular component.

Variable resistor

Used to control current and resistance in a circuit.

thermistor

Converts heat to electrical resistance.

Light-dependent resistor

Converts light to electrical resistance.

heater

Converts electrical energy to heat.

Potential divider

To provide a variable potential difference. To split the potential dierence of a power source between two or more components.

switch

In open position the circuit is broken so no current ow

transformer

A transformer is a device that transfers electric energy from one alternating- current circuit to one or more other circuits, either increasing (stepping up) or reducing (stepping down) the voltage.

magnetising coils

Electromagnetic coils are used in electrical engineering, in applications where electric currents interact with magnetic elds, in devices such as electric motors, generators, inductors, electromagnets and transformers.

Fuse

A safety device which melts to break the circuit if the electrical current owing through it exceeds a specied valu

Relay

The relay permits a small amount of electrical current to control high current loads. When voltage is supplied to the coil, small current passes through the coil, resulting in a larger amount of current passing through the contacts to control the electrical load.

generator

An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output

motor

A motor is a device that can convert electrical energy into mechanical energy.

Diode

A device which only allows current to ow in one direction

Light Emitting Diode (LED)

A diode that emits light