Definitions
What are Charge Carriers
Particles that move and carry electric charge
Current leaving and entering a junction
The total current entering a junction is equal to total current leaving
Voltage, Resistance, Current
V = IR
Resistors in series
R = R1 + R2 + R3 +...
What is Internal Resistance
The loss of potential difference per unit current in the source when current passes through
In series, the current passing through components
The current passing though components in series is the same in each component
Power, Current, Voltage
P = IV
Resistors in Parallel
1/R = 1/R1 + 1/R2 + 1/R3 +....
What is Ohms Law
The potential difference across a component is directly proportional to the current through it, under constant physical conditions
In series, total pd across all components equals
Total pd across all components equals the sum of pf across each component
Current, Charge, Time
Q = IΔ T
ε = IR + Ir
What is a Superconductor
A material that exhibits zero electrical resistance below a critical temperature
The pd across components in parallel is
The pd across components in parallel is the same
Resistivity, Resistance, Area, Length
ρ = RA/L
P = I2 R
What is the Potential Divider
A circuit that divides a voltage into two or more smaller voltages, using two or more resistors in series
Sum of emf round the circuit is equal to
Sum of emf round the circuit is equal to sum of potential drops
Power, Current, Resistance
P = I² × R
V = ε - Ir/n