electricity gcse physics aqa

what is this circuit symbol

thermistor

what is this circuit symbol

light emitting diode

what is this circuit symbol

light dependent resistor

what is this circuit symbol

diode

what is this circuit symbol

fuse 

which line of a battery represents positive

longer line

what way does electrons flow

negative to postive

what way does convectional current travel?

positive to negative 

what is a short circuit

where there is a path in the circuit that doesn’t go through a component.

ohm’s law

the current of a component is directly proportional to the potential difference across it if the temperature is constant

what is an ohmic conductor

a component that follows ohm’s law 

2 examples of ohmic conductors

wire, fixed resistor

2 examples of components that aren’t ohmic

diodes, filament lamps

what are i-v characteristics

current-potential difference graphs

what are linear components?

components with constant resistance that have straight line graphs

what is the relationship between resistance and current in a filament lamp?

the more current that flows through the lamp, the more the resistance increases

what is the relationship between resistance and current in a diode?

current only flows one way so resistance is initially high but drops as the potential difference increases letting current flow

what happens to resistance in a LDR

it decreases in bright light and increases in darkness

what happens to resistance in a thermistor

it decreases in hot conditions and increases in cool conditions

one example where are themistors useful

thermostats

why does the movement of a charge transfer energy?

the charge does work against the resistance of the circuit and work done is the same as energy transferred