Electricity Flashcards
Define current.
The rate of flow of charge.
Potential difference is …
Is the work done in moving a unit charge between 2 points.
Define 1 coulomb.
The amount of charge that passes a point when the current is 1 A over 1 second.
What is the equation relating current to charge?
I =
The potential difference is one volt when ….
1 volt = when it takes 1 joule to move 1 coulomb of charge through a component.
Voltage equation, v=
In terms of Q
V = work done / charge
Ammeters must be in
Series
Voltmeters must be in
Parallel
Resistance equation in terms of volts
R = V/I
Ohm’s law states that …
That provided a constant temperature the current through an omic conductor will be directly proportional to the potential difference across it.
Why do filament lamps blow when they are switched on?
Because there is a high initial current as it starts cold.
There is a raid temperature increase.
These could both cause the filament to burn up and blow.
What is a potential divider?
It is a circuit with resistors and an output voltage. The voltage across One of the resistors is used for the output voltage. If the resistance is not fixed the output voltage can be variable.
What equations can you use to calculate potential dividers?
V1/v2=R1/R2
V output = R1/Rt x Vinitial
How is resistance calculate for resistors in series?
Rt= R1 + R2 + ….
How is resistance calculated for resistors in parallel?
1/Rt = 1/R1 + 1/R2 + 1/R3 + …
