series circuit
parallel circuit
Cell
store of chemical energy
Battery
two or more cells in series
Switch
breaks circuit, turning current off
Lamp
lights when current flows
Ammeter
measures current
Voltmeter
measures potential difference
Diode
current flows one way
LED
emits light when current flows
LDR
resistance low in bright light
Fuse
melts when current is too high
Resistor
affects the size of current flowing
Variable resistor
allows current to be varied
Thermistor
resistance low at high temp