Electricity and magnetism: current, voltage (potential difference), charge, resistance; relationships between them and links to energy and power. Elementary circuits including batteries, wires, resistors, filament lamps, diodes, capacitors, light dependent resistors and thermistors; series and parallel circuits. Elementary electrostatic forces and magnetism (mathematical treatment not required). Links between electricity and magnetism; electromagnets, motors, generators and transformers. Current as a flow of electrons; thermionic emission and energy of accelerated electron beams.