ElectricityCurrentVoltage

ResistanceCurrent, Voltage, Resistance characteristics

AC DCPlugsEarthFusesPower

Current

• Current is the amount of charge flowing past a point in a given time

Current (A) = Charge (C) / time (s)

Current read by an ammeter – connected in series

Potential Difference

• Voltage• Potential difference is the energy

given to or given by a charge when it passes a component.

PD (V) = Energy (J) / Charge (C)

PD is taken by a voltmeter and is connected in parallel with the

component.

Resistance

• Resistance is the volts per amp for a component.

• How many volts are needed to push a current of so many through a component.

Resistance (Ohms) = PD (V)/ Current (A)

• Circuit models• Circuit diagrams• Resistor models

IV Characteristics

• Resistor• Bulb• Diode

Resistors

• Thermistor• LDR

• review

Mains Elec

• PHET• AC DC• Period and frequency

Plugs

Fuse• A Fuse is a piece of wire with a low

melting point• If there is a fault in the electrical

appliance and the current goes up it could damage the wiring in the appliance

• But if a fuse is installed, this will melt (or “blow”) and break the circuit

• So a fuse is used to protect the appliance – not necessarily to protect us from electric shock

Earth

• What on Earth does it do?• V d G

Earth

• No Earth – No Fault

Earth

• No Earth - Fault

Earth

• Earth – no Fault

Earth

• Earth - Fault

Power

• Power = work done / time taken

• Lifting stuff

Electrical Power

• Electrical power is the electrical work done in a given time.

Power (W) = current (A) x voltage (V)