1. What is a Wheatstone Bridge?

The Wheatstone bridge is an electrical circuit used to measure an unknown electrical resistance by balancing two legs of a bridge circuit. It's commonly used in strain gauge and resistance thermometer measurements.

2. How Does the Calculator Work?

The calculator uses the Wheatstone bridge formula:

Where:

• \( V_b \) — Bridge voltage (V)
• \( V \) — Supply voltage (V)
• \( R_x \) — Unknown resistance (Ω)
• \( R_1, R_2, R_3 \) — Known resistances (Ω)

Explanation: The bridge is balanced when \( V_b = 0 \), which occurs when \( \frac{R_x}{R_3} = \frac{R_2}{R_1} \). When unbalanced, the voltage difference can be measured and used to calculate the unknown resistance.

3. Importance of Bridge Voltage

Details: The bridge voltage indicates the degree of imbalance in the circuit. A null detector can be used to find the balance point for precise resistance measurements.

4. Using the Calculator

Tips: Enter all resistance values in ohms (Ω) and supply voltage in volts (V). All values must be positive numbers. For balanced bridge conditions, the result will be 0V.

5. Frequently Asked Questions (FAQ)

Q1: What is a balanced Wheatstone bridge?
A: A bridge is balanced when \( R_x/R_3 = R_2/R_1 \), resulting in zero voltage across the bridge (V_b = 0).

Q2: How sensitive is the Wheatstone bridge?
A: The sensitivity depends on the supply voltage and the resistance values. Higher voltages generally provide better sensitivity but may cause self-heating.

Q3: What are typical applications?
A: Used in strain gauges, temperature sensors, light detectors, and other precision resistance measurements.

Q4: What's the advantage over simple resistance measurement?
A: The bridge configuration cancels out many sources of error and allows for very precise measurements.

Q5: Can I use this for very small resistances?
A: For very small resistances, a Kelvin bridge (modified Wheatstone bridge) is more appropriate to account for lead resistances.