Enter the electromotive force, current, and load resistance into the calculator to determine the internal resistance.
Internal Resistance Formula
The following formula is used to calculate an internal resistance.
r = (e / i) – R
- Where r is the internal resistance (ohms)
- e is the electromotive force (Volts)
- i is the current (amps)
- R is the resistance of the load in the circuit.
Internal Resistance Definition
Internal resistance is the total resistance to electron flow that arises from the internal structures of a circuit.
Internal Resistance Example
How to calculate the internal resistance?
- First, determine the electromotive force.
For this example we will say this value is 10 V.
- Next, determine the current.
For this example we will assume a current of 10 amps.
- Next, determine the load resistance.
For this example the value is 20 ohms.
- Finally, calculate the internal resistance.
Using the formula we find the internal resistance to be: 10/10 – 20 = -19 ohms.