Why voltage should have small internal resistance

Answer 1

The internal resistance of a voltage source, such as a battery or power supply, plays a crucial role in its overall performance. Here are several reasons why it is beneficial for voltage sources to have low internal resistance:

1. Maximized Power Delivery: Lower internal resistance allows the voltage source to deliver more power to the load. Power loss due to internal resistance is given by the formula \( P_{\text{loss}} = I^2 R_{\text{internal}} \), where \( I \) is the current flowing through the circuit. If the internal resistance is high, more power is wasted as heat, reducing the efficiency of the system.

2. Minimized Voltage Drop: A voltage source with high internal resistance will experience a significant voltage drop when current flows. This drop can lead to a lower voltage than intended at the load, affecting the performance of devices powered by the source. In contrast, low internal resistance helps maintain a stable output voltage despite variations in load current.

3. Improved Load Response: Devices that draw varying currents (like motors or amplifiers) can cause fluctuations in the voltage output of a source with high internal resistance. A low internal resistance allows for a more consistent voltage delivery even under changing load conditions, contributing to better performance and reliability.

4. Higher Efficiency: Low internal resistance contributes to overall system efficiency, particularly in applications like power supplies and battery systems. This efficiency is critical in battery-operated devices where maximizing operational time is essential.

5. Reduced Heating: High internal resistance can lead to significant heat generation due to power loss. Excessive heat can cause components to degrade, reduce the lifespan of the device, and pose safety risks. Lower resistance minimizes this heating effect.

6. Better Compatibility with Load Types: Many electronic components and systems operate optimally with minimal voltage variations. Low internal resistance ensures that such components receive the appropriate voltage for effective operation.

In summary, low internal resistance in voltage sources contributes to more efficient power delivery, stable voltage output, improved device performance, reduced heat generation, and overall better system reliability.