Current, potential difference, power and resistanceResistors in series
Current, potential difference, power and resistance can be calculated to analyse circuits including potential dividers and Wheatstone bridges. Calculations may involve several steps.
When resistors are connected in series, the current through each resistor is the same. In other words, the currentMoving electric charges, eg electrons moving through a metal wire. is the same at all points in a series circuit.
So in the circuit above \(I_{S}=I_{1}=I_{2}=I_{3}\)
Potential difference
When resistors are connected in series, the total of all the potential differences (sometimes referred to simply as voltage) around the circuitA closed loop through which current moves - from a power source, through a series of components, and back into the power source. is equal to the potential difference (p.d.) of the supply:
\(V_{S} = V_{1}+V_{2}+V_{3}\)
This relationship expresses the law of conservation of energy.
The supply voltage is a measure of the energy supplied to each electron. The p.d. across each component is the energy converted by each component. Therefore the energy supplied equals the energy converted 鈥 energy has been neither created nor destroyed in the circuit.
Resistance
The total resistance of a number of resistorAn electrical component that restricts the flow of electrical charge. Fixed-value resistors do not change their resistance, but with variable resistors it is possible to vary the resistance. in series is equal to the sum of all the individual resistances.