Electricity Flashcards
Electrical Current
The electric charge transferred per second.
Direct Current (d.c.)
The flow of current in one direction only.
Alternating Current (a.c.)
The back and forth flow of current.
Current changes direction every fraction of a second.
Electric Field
A force field that surrounds any electric charge.
Potential Difference (Voltage)
The energy supplied to each coulomb of charge that passes through a power supply.
Mains Voltage
The voltage supplied to any electrical device plugged into the mains.
In the UK, this is 230 V.
Resistance
The opposition to current flow.
Ohm’s Law
For a fixed temperature, the voltage across a conductor is directly proportional to the current passing through it.
Ohmic Conductor
A component that obeys Ohm’s law.
Non-Ohmic Conductor
A component that does not obey Ohm’s law.
Series Circuit
A circuit in which all components are connected one after the other and there is only one path for the current to flow.
Parallel Circuit
A circuit in which there is more than one path (branch) for the current to flow.
Cell
A component used to power a circuit.
Battery
A collection of two or more cells.
Bulb/Lamp
A component that converts electrical energy to light energy.
Switch
A component that allows a circuit to be turned on/off.
Resistor
A component that opposes the flow of current.
Variable Resistor
A component that allows the flow of current in a circuit to be changed.
Ammeter
A component used to measure the current in a circuit.
Voltmeter
A device used to measure the voltage across a circuit component.
Ohmmeter
A device used to measure the resistance of a circuit component.
Motor
A component that converts electrical energy to mechanical energy.
D.C. Supply
A component that produces a constant voltage.
A.C. Supply
A component that produces an alternating voltage.
Diode
A component that allows current to flow in one direction only.
Capacitor
A component that stores charge and therefore electrical energy.
Microphone
A component that converts sound energy to electrical energy.
Loudspeaker
A component that converts electrical energy to sound energy.
Thermocouple
A component that converts heat energy into electrical energy.
Solar/Photovoltaic Cell
A component that converts light energy into electrical energy.
Thermistor
A temperature-dependent resistor whose resistance varies with temperature.
LDR
A light-dependent resistor whose resistance varies with light intensity.
LED (Light Emitting Diode)
A type of diode that converts electrical energy to light energy.
Potential Divider
An arrangement of two or more resistors in series where the voltage from the supply splits across each resistor.
Transistor
A semiconductor device that can be used as an electronic switch.
NPN Transistor
A type of transistor that will switch on when the voltage across it reaches 0.7 V.
MOSFET
A type of transistor that will switch on when the voltage across it reaches 2.0 V.
Time Delay Circuit
A circuit, involving a capacitor and switch, in which there is a delay between switching on and the device turning on.
Relay Switch
A device consisting of an electromagnetic coil and switch that can be used to control a high voltage circuit using a safe low voltage circuit.
Electrical Power
The electrical energy transferred per second.
Fuse
A safety device containing a thin wire which will break (melt) when too large a current flows through it.
