Generating Electricity

Electricity

The movement/flow of electric charge.

Particle that moves through metal wires

Electrons.

Charge of an electron

Negative (−).

Direction electrons move in a metal circuit

From negative (−) to positive (+).

Conventional current

The agreed direction of current from positive (+) to negative (−).

Conductor

A material that allows electric current to flow easily.

Examples of conductors

Copper, aluminium and iron.

Insulator

A material that does not allow electric current to flow easily.

Examples of insulators

Plastic, rubber and glass.

Property determining how easily electricity flows through a material

Electrical conductivity.

Static electricity

A build-up of electric charge in one place.

Current electricity

The continuous flow of electric charge through a conductor.

What happens when an object loses electrons

It becomes positively charged.

What happens when an object gains electrons

It becomes negatively charged.

Charge of a proton

Positive (+).

Charge of a neutron

Neutral/no charge.

Behavior between like charges

They repel.

Behavior between opposite charges

They attract.

Requirement for current to flow

A complete/closed circuit.

What happens when a circuit is open

Current cannot flow.

Series circuit

A circuit with one pathway for current.

Parallel circuit

A circuit with two or more pathways for current.

Current behavior in a series circuit

It is the same throughout the circuit.

Current behavior in a parallel circuit

It splits between the different branches.

Voltage behavior in a series circuit

It is shared between the components.

Voltage behavior across branches in a parallel circuit

Each branch has the same voltage as the supply.

What happens if one globe breaks in a series circuit

All the globes stop working.

What happens if one globe breaks in a parallel circuit

The other branches can continue working.

Brightness of globes in series

They are generally dimmer because they share the voltage.

Major advantage of parallel circuits

Devices can work independently, so one breaking doesn't necessarily stop the others.

Current

The rate of flow of electric charge.

Symbol and unit for current

Symbol = I; unit = ampere (A).

Instrument that measures current

An ammeter.

How an ammeter is connected

In series.

Voltage

The push/energy that causes electric charge to move.

Symbol and unit for voltage

Symbol = V; unit = volt (V).

Instrument that measures voltage

A voltmeter.

How a voltmeter is connected

In parallel across the component.

Resistance

The opposition to the flow of electric current.

Symbol and unit for resistance

Symbol = R; unit = ohm (Ω).

Ohm's Law

V = I × R.

Formula for current using Ohm's Law

I = V ÷ R.

Formula for resistance using Ohm's Law

R = V ÷ I.

What happens to current when voltage increases, if resistance stays constant

Current increases.

What happens to current when resistance increases, if voltage stays constant

Current decreases.

DC electricity

Direct current that flows in one direction.

AC electricity

Alternating current that repeatedly changes direction.

Electrical power

The rate at which electrical energy is transferred or used.

Formula for electrical power

P = V × I.

Formula connecting power, energy and time

P = E ÷ t.