Calculating Total Resistance in Series
When resistors are connected in series, they are placed "end-to-end" so that the electric current has only one single path to follow. Because the current must pass through every resistor in succession, the total resistance of the circuit increases.
Key Principles of Series Circuits
- Same Current: The current flowing through every resistor in the series is exactly the same.
- Additive Resistance: The equivalent resistance ($R_{eq}$) is simply the sum of all individual resistances.
- Voltage Drop: The total voltage from the power source is shared among the resistors. The resistor with the highest resistance will have the largest "voltage drop" across it.
The Formula
Where:
=
Equivalent Resistance=
Individual ResistancesExample Calculation
You connect three resistors in series: $10 , \Omega$, $22 , \Omega$, and $47 , \Omega$.
- Sum them up: $10 + 22 + 47 = 79 , \Omega$.
The total equivalent resistance is $79 , \Omega$.