Internal Resistance Calculator

Formula

The formula to calculate the Internal Resistance (r) is:

\[ r = \frac{e}{i} - R \]

Where:

\( r \) is the Internal Resistance (ohms)
\( e \) is the Electromotive Force (Volts)
\( i \) is the Current (amps)
\( R \) is the Load Resistance (ohms)

Internal Resistance Definition

Internal resistance is the total resistance to electron flow that arises from the internal structures of a circuit. It affects the efficiency and performance of electrical devices and is an important factor in circuit design and analysis.

Example Calculation

Let's consider an example:

Electromotive Force (e): 12 Volts
Current (i): 2 Amps
Load Resistance (R): 4 Ohms

Using the formula to calculate the Internal Resistance:

\[ r = \frac{12}{2} - 4 = 2 \, \text{Ohms} \]

This demonstrates that with an electromotive force of 12 Volts, a current of 2 Amps, and a load resistance of 4 Ohms, the internal resistance would be 2 Ohms.