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Electricity
Term | Definition |
---|---|
Alternating Current | Current that alternates or changes direction. Mains electricity does this 50 times a second (50Hz) |
Ammeter | Measures the size of the current travelling through a circuit |
Battery | Two or more cells joined together |
Cell | Component that converts chemical potential energy into electrical energy |
Circuit | Continuous pathway through which electrons can flow |
Conductor | A substance whose electrons can travel freely (e.g. metals) |
Conventional current | The flow of current from positive to negative around a circuit |
Current | Flow of electrons around a circuit measure in amps (A) |
Diode | Component which only lets current travel in one direction |
Direct current | Current that only flows in one direction. Batteries produce d.c |
Electricity | Movement of electrons through a conductor |
Electron flow | The flow of negative charges from negative to positive around a circuit. |
Fuse | Thin wire which melts or "blows" and breaks a circuit if the current is too large. |
Insulator | A substance that does not conduct electricity (e.g. air, rubber) |
Lamp | Component that transforms electrical energy into light energy (and heat) |
Ohmic component | A component that obeys Ohm's Law: the current through it increase proportionately with the voltage across it. The resistance stays constant. Components are non-ohmic if the temperature increases at this increased resistance. |
Parallel circuit | A circuit where the current divides and passes through different loops or branches. The voltage is the same across branches. |
Resistance | A measure of how difficult it is for current to flow around a circuit or through a component. Measured in ohms (Ω) |
Resistor | A component that restricts the flow of current. Fixed-value resistors do not change their resistance but with variable resistors (rheostats) you can change the resistance |
Series circuit | A circuit composed of a single loop (only one path for the current to flow). The current is the same everywhere but the voltage is shared between components. |
Switch | Component which allows current to flow when it is closed |
Voltage | The difference in electrical energy between two points that make a current flow, measured in volts (V). Also called potential difference. |
Voltmeter | Measures the change in voltage as it passes through a component. |
Wire | Conductor which passes electricity easily from one part of a circuit to another. |