Resistance in series and parallel circuits Flashcards
What is a series circuit
A series circuit is one loop. There is only one path for the current to take and the current is the same everywhere. Potential difference is split up across each component. It is simple to build but as more lights are added, the lights get dimmer
What is a parallel circuit
A parallel circuit is 2 or more loops. Current splits up between each branch and the total current is calculated by adding up the current of each branch. Potential difference is the same across all branches and the power source. The components are independent bur it requires more wiring.
Resistance in series circuits
To calculate the resistance in a series circuit, you add up the resistances of all the components of the circuit
Resistance of parallel circuits
In a parallel circuit, the total resistance is always smaller than the smallest branch resistance
Rt=r1+r2
Rt=Resistance total
r1=Resistance 1
r2=Resistance 2
This is only for series circuits
TR<
TR=Total Resistance
<=is smaller than the smallest branch total
This is only for parallel circuits
How to work out missing resistance
V=IR
Voltage=Current x Resistance
Rearranged to Resistance=Voltage/Current (R=V/I)
A resistor on a current-voltage graph
A straight diagonal line
A diode on a current-voltage graph
A straight horizontal line then a straight diagonal line
A filament lamp on a current-voltage graph
A “s” line
LDR and thermistor on a current-voltage graph
A “half-U” curve
Charge formula
Q=IT
Charge= Current x Time(s)
