Yr 8 Physics : Topic 1 - Electric Circuits

Electric circuit

A complete loop that allows current to flow

Current

The flow of electric charge

Current unit

Amperes or A

Ammeter

An instrument used to measure current

Ammeter connection

An ammeter is connected in series

Series circuit

A circuit with one path for current

Series current

The current is the same everywhere

Voltage

Energy transferred to each charge

Voltage unit

Volts or V

Voltmeter

An instrument used to measure voltage

Voltmeter connection

A voltmeter is connected in parallel

Parallel circuit

A circuit with more than one path

Parallel current

Current splits at junctions

Parallel voltage

Voltage is the same across each branch

Resistance

How much a component opposes current

Resistance unit

Ohms or Ω

Ohms law

Resistance equals voltage divided by current

Resistance equation

R equals V divided by I

Higher resistance effect

Current decreases

Longer wire

A wire with greater resistance

Current rule

Current into a junction equals current out

Series voltage

The supply voltage is shared between components