Edexcel IGCSE Physics - Electricity

Flashcards based on Electricity lecture notes for IGCSE Physics.

Cell

A simple circuit component used to light up a bulb.

Battery

A line of cells joined together end to end.

Bulb/Filament Lamp

A component that lights up when an electric current passes through it, useful for indicating current flow.

On/Off Switch

A component that stays on or off, like a light switch.

Series Circuit

Circuit where current flows through each component sequentially; if one component breaks, the circuit is broken.

Parallel Circuit

Circuit where current flows through multiple branches; if one branch breaks, the other branches continue to function.

Electric Current

The flow of charge, carried by electrons.

Direction of Electron Flow

Flow of electrons in the direction away from the negative terminal and towards the positive terminal.

Direction of Conventional Current

Direction of current from the positive terminal to the negative terminal of the battery.

Electric Current

The rate of flow of charges, measured in amperes (A).

Electric Charge (Q)

Measured in coulombs (C), the charge equivalent to that carried by electrons.

Ammeter

A device used to measure the size of the current flowing in a circuit, connected in series.

Direct Current (D.C.)

Supply with a constant e.m.f. polarity, where current flows in the same direction.

Alternating Current (A.C.)

Supply with a varying e.m.f. magnitude and alternating polarity, voltage changes continuously, and current direction reverses.

Potential Difference (Voltage)

The energy transferred per unit charge, measured in volts (V), where 1 Volt = 1 J/C.

Voltmeter

A device used to measure the voltage across a component in a circuit, connected in parallel.

Resistance

The ratio of the potential difference applied across a conductor to the current passing through it, measured in Ohms (Ω).

Fixed Resistor

A resistor with a constant value.

Variable Resistor (Rheostat)

A resistor with a range of values that can be changed manually to vary the current in the circuit.

Thermistor

A component used as a temperature sensor; its resistance decreases as temperature increases.

Light-Dependent Resistor (LDR)

A component used to detect light levels; its resistance decreases as light intensity increases.

Diode

A component that allows current to flow in one direction only.

Forward Bias

Condition where a diode has extremely low resistance, allowing current to flow.

Reverse Bias

Condition where a diode has extremely high resistance, blocking current flow.

Light-Emitting Diode (LED)

A diode that produces light when a current flows through it in the forward direction.

Current in series

The current at all points around the circuit is always the same

Current in parallel

The current splits between the branches of the circuit

Voltage in series

The voltage is split (or shared) between the components

Voltage in parallel

The voltage across all components in a parallel circuit is the same

Live Wire

The wire connected to the power station

Neutral Wire

The 'return wire' completing the circuit back to the power station

Earth Wire

The third wire that is frequently missing in some plugs, along with the third pin

Cable Grip

Locks the cable in place, preventing someone pulling on the connections

Fuse

Consists of a thin metal wire, mounted inside a short cylinder the fuse is designed to melt when a specific current passes through it

Circuit breakers

Open a switch if the current gets too high, and this breaks the circuit

Insulation

Preventative measure by Copper cables with a substance such as plastic

Double insulation

Some devices do not need an earth wire, The symbol for a double insulated device is 2 squares, one inside the other

The earth wire

The earth wire is connected to the metal casing of the appliance, and leads into the ground

Identical Charges

Charges repel

Opposite Charges

Charges attract