Physics - Electricity definitions

Electric current

The flow of electrons from the negative terminal to the positive terminal of a cell

Conventional current

moves in the opposite direction to the actual electron flow

Voltage / potential difference

The ability to give electrons the ‘push’ they need to carry charge around a circuit

Tells you how much electrical energy has been converted into other forms of energy

Volts (V)

Unit of voltage

I

Symbol for current

Current

Rate of flow of charge

Q

symbol for charge

Charge

Supplied by electrons, and an electron has a charge of -1.6 × 10^-19c

Coulomb (C)

Measurement for (electical)charge

Q =1.6 × 10^-19C

Amperes (A)

Measurement for current

1A = the movement of one coulomb of charge

Series Circuit

all components are connected end-to-end to form a single path for current flow

Series Circuit - Current Rule

The current is the same everywhere

Series Circuit - Voltage Rule

The voltage in each path is the same

Parallel circuit

one that has two or more paths for the electricity to flow

Parallel circuit - Current Rule

The current spilts and rejoins at junctions

Parallel circuit - Voltage Rule

The voltage in each path is the same

Ammeter

Measures current

Voltmeter

Measures voltage

Ohm’s Law

The current flowing throught a wire is proportional to the voltage across the wire as long as the temperature of the wire remains constant

Resistance

A property of materials, and it is a measure of how the components in a circuit try to resist, the flow of current

• Conductors have a low resistance

• Insulators have a high resistance