Wheatstone Bridge: Full Explanation
1. Introduction to Wheatstone Bridge
The Wheatstone bridge is an electrical circuit used to measure an unknown resistance by balancing
two legs of a bridge circuit. It was invented by Samuel Hunter Christie in 1833 and later popularized
by Sir Charles Wheatstone in 1843.
2. Principle of Wheatstone Bridge
The bridge works on the principle of null deflection. When the bridge is balanced, the ratio of
resistances in one leg is equal to the ratio of resistances in the other leg, leading to no current
through the galvanometer.
3. Circuit Diagram and Explanation
The Wheatstone bridge consists of four resistors connected in a diamond shape. A voltage source is
applied across the bridge, and a galvanometer is used to detect the balance condition.
4. Derivation of the Wheatstone Bridge Formula
For a balanced bridge:
(R1 / R2) = (R3 / R4)
Where R1, R2, R3, and R4 are the four resistances. If three are known, the fourth can be calculated.
5. Applications of Wheatstone Bridge
- Measuring unknown resistances in laboratories.
- Used in temperature sensors (thermistors) and strain gauges.
- Applied in industrial instrumentation for precise resistance measurement.
6. Advantages and Limitations
- High accuracy and sensitivity.
- Affected by temperature changes and external interference.
- Not suitable for very high or very low resistance measurements.
7. Conclusion
The Wheatstone bridge is a fundamental electrical circuit used for precise resistance measurement.
Its accuracy and reliability make it an essential tool in both scientific research and industrial
applications.
1. Introduction to Wheatstone Bridge
The Wheatstone bridge is an electrical circuit used to measure an unknown resistance by balancing
two legs of a bridge circuit. It was invented by Samuel Hunter Christie in 1833 and later popularized
by Sir Charles Wheatstone in 1843.
2. Principle of Wheatstone Bridge
The bridge works on the principle of null deflection. When the bridge is balanced, the ratio of
resistances in one leg is equal to the ratio of resistances in the other leg, leading to no current
through the galvanometer.
3. Circuit Diagram and Explanation
The Wheatstone bridge consists of four resistors connected in a diamond shape. A voltage source is
applied across the bridge, and a galvanometer is used to detect the balance condition.
4. Derivation of the Wheatstone Bridge Formula
For a balanced bridge:
(R1 / R2) = (R3 / R4)
Where R1, R2, R3, and R4 are the four resistances. If three are known, the fourth can be calculated.
5. Applications of Wheatstone Bridge
- Measuring unknown resistances in laboratories.
- Used in temperature sensors (thermistors) and strain gauges.
- Applied in industrial instrumentation for precise resistance measurement.
6. Advantages and Limitations
- High accuracy and sensitivity.
- Affected by temperature changes and external interference.
- Not suitable for very high or very low resistance measurements.
7. Conclusion
The Wheatstone bridge is a fundamental electrical circuit used for precise resistance measurement.
Its accuracy and reliability make it an essential tool in both scientific research and industrial
applications.
