1. What Is The Voltage Equation?

The voltage equation \( V = E - I \times r \) calculates the terminal voltage in an electrical circuit, where E is the electromotive force (emf), I is the current, and r is the internal resistance of the power source.

2. How Does The Calculator Work?

The calculator uses the voltage equation:

Where:

• \( V \) — Terminal voltage (V)
• \( E \) — Electromotive force (V)
• \( I \) — Current (A)
• \( r \) — Internal resistance (Ω)

Explanation: This equation accounts for the voltage drop across the internal resistance of the power source, giving the actual voltage available to the external circuit.

3. Importance Of Voltage Calculation

Details: Accurate voltage calculation is essential for designing and analyzing electrical circuits, ensuring proper operation of components, and troubleshooting power supply issues.

4. Using The Calculator

Tips: Enter electromotive force in volts, current in amperes, and internal resistance in ohms. All values must be valid (positive numbers).

5. Frequently Asked Questions (FAQ)

Q1: What is electromotive force (emf)?
A: EMF is the maximum potential difference provided by a power source when no current is flowing. It represents the ideal voltage output.

Q2: Why does voltage drop occur?
A: Voltage drop occurs due to the internal resistance of the power source, which causes energy loss when current flows through it.

Q3: What are typical values for internal resistance?
A: Internal resistance varies by power source type. Batteries typically have low internal resistance (milliohms to ohms), while other sources may have higher values.

Q4: Can voltage be higher than emf?
A: No, the terminal voltage V is always less than or equal to the emf E in this equation, as current flow causes a voltage drop.

Q5: When is this equation most applicable?
A: This equation is particularly useful for analyzing battery-powered circuits and other DC power systems with significant internal resistance.