Topic 2 - Electricity Flashcards
(25 cards)
Alternating Potential Difference
A continually oscillating current flow, which
results in the potential difference across two points continually oscillating between
a positive and negative value.
Amperes (Amps)
The unit of current.
Attraction
A force pulling two opposite charges together, when they are brought
near each other
Coulomb
The unit of charge.
Diode
A component that only allows current to flow through in the forward
direction. They have very large resistances in the reverse direction.
Direct Potential Difference
A one-directional current flow
Earth Wire
The green and yellow striped safety wire that prevents an appliance
from becoming live.
Electric Field Lines
Lines representing an electric field, that point in the
direction in which a positive charge would experience an electric force.
Electric Field
A region in which a charge will experience a non-contact, electric
force. All charged objects have an electric field around them, and this field is
stronger the closer you are to the charge.
Electrical Current
The rate of flow of electrical charge. Its value is the same at
any position in a single closed loop.
Light Dependent Resistor (LDR)
A light sensitive component whose resistance
increases as its temperature decreases.
Live Wire
The brown coloured wire that carries the alternating current from the
supply in a mains power supply.
Neutral Wire
The blue coloured wire that completes the circuit in a mains power
supply.
Non-Contact Force
A force experienced between two separated objects.
Examples include gravity, and magnetic and electric forces.
Ohmic Conductor
A conductor whose current flow is directly proportional to the
potential difference across it, when held at a constant temperature.
Ohms
The unit of resistance.
Parallel
Components connected in parallel have the same potential difference
across each component. The total current is equal to the sum of the currents
flowing through each component.
Resistors in Parallel
The total resistance is equal to the inverse of the sum of
the inverses of the resistance of the parallel components. The total resistance of
two parallel resistors is always less than the lowest individual resistor value.
Resistors in Series
The total resistance is equal to the sum of the resistances of
the individual components
Series
Components connected in series have the same current passing through
each component but share the total potential difference of the power supply.
Static Charge
The charge caused by an imbalance of positive and negative
charges in, or on, an object’s surface. It is often caused by electrons being rubbed
from one surface onto another.
Step-Down Transformers
Devices found between the transmission cables and
the consumer that lower the potential difference of the power so it is at safe,
usable levels.
Step-Up Transformers
Devices that increase the potential difference generated
by a power station, so that the electrical power transmitted along the transmission
cables is at a higher potential.
The National Grid
The network of power stations, transformers and cables that
connect consumers to power stations.
