electricity and electronics:

Voltage

an electromagnetic force or potential difference expressed in volts.

Astable Circut

a circuit with no stable state. the state continuously changes.

Polarity

Electric Current flowing from + to -. device that only works when connect to a particular circuit.

Current

Flow of electricity which results from the ordered directional movement of electrically charged particles.

Resistance

the measure of the difficulty with which electrons move through a material or electrical components.

resistor

devices providing different levels of resistance to electric current.

Frequency

how often an AC cycle repeats

Semiconductor

Materials that have resistance levels between those of a conductor and insulator.

Polarised

The component must be connected the right way round with + leg connected to + power supply.

Diodes

semiconductor device that allow current to flow in one direction only.

Transistors

Sensitive electronic switches, the main process components used in most electronic devices.

Solenoid

An electrical device that converts electric current to movement in a straight line

Relay

A mechanical switch that is electrically activated.

Product recycling fund (PRF)

The charge applied to offset the cost of recycling electrical goods. It is applied to the purchase price and varies according to the type of electrical item

Analogue signal

Continuously variable signal/system.

Digital signal

A signal/system with discrete value, one of a number of distinct possible values, usually 1 and 0