The Wheatstone bridge illustrates the concept of a difference measurement, which can be extremely accurate
Naty1 said:Its a clever use of resistors (or other elements) in a circuit to enhance accuracy of measurements. As the reference above explains
A Wheatstone bridge is a type of electrical circuit that is used to measure an unknown electrical resistance by balancing two legs of a bridge circuit. It was invented by Samuel Hunter Christie in 1833 and later improved upon by Sir Charles Wheatstone in 1843.
A Wheatstone bridge consists of four resistors, with two resistors on each side of the bridge. An unknown resistance is placed in one of the legs, and a known resistance is placed in another leg. A voltage source is connected to the two ends of the bridge, and the voltage drop across the unknown resistance is measured. By adjusting the known resistance, the voltage drop can be balanced, and the unknown resistance can be calculated using the principle of electrical resistance.
The main components of a Wheatstone bridge include a voltage source, four resistors, and a galvanometer or voltmeter to measure the voltage drop. The resistors can be either fixed or adjustable, with the adjustable resistor used to balance the bridge. Some modern Wheatstone bridges may also include additional components such as amplifiers or digital displays.
Wheatstone bridges have many practical applications in electrical engineering and physics, such as measuring unknown resistances, determining the temperature coefficient of a material, and detecting small changes in resistance. They are also commonly used in strain gauge measurements for industrial applications, such as measuring the stress and strain of a structure.
While Wheatstone bridges are useful for measuring unknown resistances, they do have some limitations. The accuracy of the measurements can be affected by factors such as temperature changes, wire resistance, and contact resistance. Additionally, Wheatstone bridges are not suitable for measuring very low or very high resistances.