Circuits GapFill

Electricity is used for a wide variety of applications, from the computer you're using right now, to lighting, music, cars and industrial processes. For an electrical circuit to function it needs  a closed loop and a power sourcea high resistancea power sourcea closed loop.
We discuss electricity in terms of current, which is  how much the circuit opposes the flow of chargethe energy carried per chargethe rate of flow of chargethe power dissipated by the circuit, potential difference, which is  the power dissipated by the circuitthe rate of flow of chargehow much the circuit opposes the flow of chargethe energy carried per charge, and resistance, which is  the energy carried per chargehow much the circuit opposes the flow of chargethe rate of flow of chargethe power dissipated by the circuit.
Current has units of  volts (V)ohms (Ω)watts (W)amps (A). Potential difference has units of  ohms (Ω)volts (V)amps (A)watts (W). Resistance has units of  amps (A)watts (W)volts (V)ohms (Ω).
Components are placed in a circuit and may have different properties depending on current and potential difference.
 An LDRA filament bulbAn ohmic conductorA diode has a constant resistance, no matter the current through it or the potential difference across it.
The resistance of  an ohmic conductoran LDRa diodea filament bulb increases with the current through it, as the component heats up.
 An ohmic conductorAn LDRA diodeA filament bulb only allows current to flow through in one direction.
The resistance of  a filament bulba diodean ohmic conductoran LDR changes with how much light it is exposed to, whereas in a thermistor, the resistance will decrease as the temperature  changesincreasesdecreasesdissipates. Using a variable resistor, the resistance of a circuit can be changed. A variable resistor is often used to alter the  currentenergyheat outputvoltage in a circuit; for instance, in a light dimmer switch. The power of an electrical circuit is the  energycurrentvoltsJoules (J) transferred per second and is measured in watts.
When components are arranged along the same loop of a circuit, they are in  potentialparallelseriesground; if components are arranged along different loops of the same circuit, they are in  potentialseriesgroundparallel.