What is Internal Resistance and Why Should You Care?
Internal resistance refers to the opposition to the flow of electrons within the internal components of an electrical circuit. Imagine trying to run at full speed through a crowded room; the people crowding around represent the internal resistance that slows down the flow of electric current.
Why should you care? Knowing the internal resistance can help improve the efficiency and performance of electrical systems. Whether you're a DIY electronics hobbyist, an engineering student, or a seasoned professional, understanding internal resistance can help you design better and troubleshoot quicker.
How to Calculate Internal Resistance
Here's the formula:
[\text{Internal Resistance} = \frac{\text{Electromotive Force}}{\text{Current}} - \text{Load Resistance}]
Where:
- Internal Resistance is the total resistance within the circuit (ฮฉ)
- Electromotive Force is the voltage provided by the power source (V)
- Current is the flow of electric charge (A)
- Load Resistance is the resistance presented by the external load (ฮฉ)
Calculation Example
Imagine we have the following values:
- Electromotive Force (EMF): 12 V
- Current: 2 A
- Load Resistance: 4 ฮฉ
Calculate step by step:
[\text{Internal Resistance} = \frac{12 \text{ V}}{2 \text{ A}} - 4 \text{ ฮฉ}]
[\text{Internal Resistance} = 6 \text{ ฮฉ} - 4 \text{ ฮฉ} = 2 \text{ ฮฉ}]
The internal resistance of this circuit is 2 ohms.
| Variable | Value |
|---|---|
| Electromotive Force (EMF) | 12 V |
| Current | 2 A |
| Load Resistance | 4 ฮฉ |
| Internal Resistance | 2 ฮฉ |