Resistor A resistor restricts the flow of charge. Uses include limiting the current passing through an LED, and slowly charging a capacitor in a timing circuit. Some publications use the old resistor symbol
The diagram shows a simple circuit of a battery, wires, a switch and a lamp. The switch works by breaking the circuit.
Electricity is the flow of charge around a circuit carrying energy from the battery (or power supply) to components such as lamps and motors.
Galvanometer A very sensitive meter used to measure tiny currents, usually 1mA or less.