P4 Electric circuits

Electron

a subatomic particle that has a negative charge

Conductor

A material through which charges can easily flow

Insulator

a material through which charges cannot easily flow

Circuit

an electrical device that provides a path for electrical current to flow

Series circuit

circuit that has only one path for electric current to follow

Parallel circuit

a closed circuit in which the current divides into two or more paths before recombining to complete the circuit

Charge (Q)

Fundamental property of matter that produces all electrical effects

Current (I)

the rate that electric charges move through a conductor

Amperes (A)

a unit of electric current

Ammeter

a meter that measures the flow of electrical current in amperes

Voltage (V)

the energy transferred per unit charge by an electrical component

Potential Difference (p.d.)

the energy transferred per unit charge from electrical energy into other energy forms by a device

Volt (V)

The unit for the potential difference (voltage).

Voltmeter

A device that measures potential differences in volts and is placed in parallel across a part of the circuit

Resistance (R)

a material's opposition to the flow of electric current

Ohm

the unit for resistance

Ohm's Law

States that the direct current flowing in an electric circuit is directly proportional to the voltage applied to the circuit.

Thermistor

A semiconductor device that changes resistance with a change in temperature.

Filament Bulb

electric lamp consisting of a wire filament (usually tungsten) that emits light when heated

Diode

A semi-conductor that only allows current to flow one way

Light dependant resistor (LDR)

A non-ohmic device that decreases in resistance when the light intensity increases