Electric symbols

Cell and battery of cells

Lamp

Switch

Ammeter

Voltmeter

Resistor

Variable resistor (rheostat)

Bell/buzzer

Thermistor Resistance decreases with increasing temperature Temp Resistance

Light-dependent resistor (LDR) High resistance in the dark but a low resistance in light

Diode Allows current to flow in one direction only (from + to – in the direction of the “arrow)

Captain Jack Sparrow smoking a cigar

Two cowboys on a tandem

Two fried eggs in a frying pan

3 wizards looking down a well

ac/dc Insulation and double insulation Earthing, fuses and circuit breakers

Brainiac – Cattle fence

Gather round!

Alternating current Current changes direction 50 times a second.

Fuse Thin piece of wire which melts if the current is too high If a fault develops, this thin piece of wire melts if the current is too high Circuit breakers are sometimes used instead

Earth wire Connects metal body of appliance to earth If a live wire comes loose, current flows to earth and blows the fuse

Double insulation Some appliances have no earth wire because they have a plastic outer case The plastic case acts as an extra layer of insulation around the wires

Reading! Read carefully pages Answer the questions on both pages Finish for homework due Tuesday 13 th January