P2 Electricity Flashcards
(44 cards)
What is current
Rate of the flow of charge- coulombs per second (Q = IT)- Ampere/amps (A)
What is potential difference/voltage
Energy transferred by one coulomb of charge as it passes through a component ( volts/V)
What is the measurement of charge
Coulombs ( 6.24*10^18 electrons)
What is used to measure current
Ammeter placed in series
What is used to measure potential difference
Voltmeter in parallel
What is resistance
How much the current flow is being resisted ( ohms )
What is ohms law
Current is directly proportional to potential difference when flowing through an electrical component with fixed resistance
What are the factors effecting resistance
- Width of wire
- Temp. of wire
- Wire material
Why are bulbs non-oh mic resistors
Increasing the current raises the temperature of the wire, so the resistance is therefore raised
Why are diodes non-ohmic resistors
The have higher resistance in one direction than the other as they only allow charge to flow one way
What is a series circuit
A circuit where the electrons can only take one path
What happens tho the current around a series circuit
It is the same everywhere (because the electrons only have one path to take)
What happens to the potential difference in a series circuit
The sum of the potential difference across all the components is the same as the total potential difference of the battery (because the energy is split between all the components that use it)
What happens to the resistance around a series circuit
The sum of the circuit is the sum of each component (because the electrons go through all components)
What is a parallel circuit
A circuit where the electrons have multiple paths to go down
What happens to the current in a parallel circuits
It is split between the different branches (because the electrons takes the different pathway. Charge will be the great on the path of least resistance)
What happens to the potential difference in a parallel circuits
The same across each branch (because the electrons carry the same amount of energy)
What happens to the resistance in a parallel circuits
Decreases as more branches are added (because the more pathways the more electrons can circuit simultaneously)
What is the main difference between alternating current and direct current
DC goes in one direction
AC constantly changes direction
What is the voltage and hertz of mains electricity
230V
50Hz
Is mains electricity AC or DC
AC
What are the 5 main components of the power grid
- power station
- step up transformer
- transmission cables
- step down transformer
- consumer
What is 1 period of an AC supply
One oscillation ( 1 up and down )
What is rectifying an AC wave
Making the current flow in one direction
