# Understanding the Voltage Changes in an Unbalanced Wheatstone Bridge

• msslowlearner
In summary, an Unbalanced Wheatstone Bridge is an electrical circuit used to measure resistance. It consists of four resistors arranged in a diamond shape, with a voltage source and a galvanometer connected to opposite corners. The bridge works by using null detection to balance the circuit and calculate the resistance of one of the resistors. The main difference between a Balanced and an Unbalanced Wheatstone Bridge is the presence of an unknown resistor in the circuit. The applications of an Unbalanced Wheatstone Bridge include measuring unknown resistors, quality control and testing in industrial settings, and measuring small changes in resistance in fields like medical diagnostics and environmental monitoring. However, the limitations of an Unbalanced Wheatstone Bridge include the need for a known resistor, limitations in
msslowlearner
In an unbalanced Wheatstone Bridge, does the voltage across the resistors R1 and R2 change? In other words is VR2of balanced bridge=VR2 of unbalanced bridge?

I was trying to solve a problem that required qualitative analysis. It says VR2 does not change even though the bridge is unbalanced. How?

The Bridge Balance eqn is R1/R2 = R3/R4, where R4 is the variable resistor. At balanced condition, VR2 = VR4

sorry. I've asked this question again in the HW-CW section. Pls do not reply to this post here.

## 1. What is an Unbalanced Wheatstone Bridge?

An Unbalanced Wheatstone Bridge is a type of electrical circuit that is used to measure electrical resistance. It consists of four resistors arranged in a diamond shape, with a voltage source connected to two opposite corners and a galvanometer connected to the other two corners.

## 2. How does an Unbalanced Wheatstone Bridge work?

The Unbalanced Wheatstone Bridge works by using the principle of null detection, which means that the voltage across the galvanometer is zero when the bridge is balanced. The resistance of one of the resistors in the bridge can be calculated by varying the values of the other three resistors until the bridge is balanced.

## 3. What is the difference between a Balanced and an Unbalanced Wheatstone Bridge?

The main difference between a Balanced and an Unbalanced Wheatstone Bridge is the presence of an unknown resistor in the circuit. In a Balanced Wheatstone Bridge, all four resistors are known and the bridge is balanced when the galvanometer reads zero. In an Unbalanced Wheatstone Bridge, one resistor is unknown and the bridge is unbalanced until the unknown resistor is calculated.

## 4. What are the applications of an Unbalanced Wheatstone Bridge?

An Unbalanced Wheatstone Bridge is commonly used in laboratory experiments to measure unknown resistors. It is also used in industrial settings for quality control and testing of electronic components. Additionally, it can be used to measure small changes in resistance, making it useful in fields such as medical diagnostics and environmental monitoring.

## 5. What are the limitations of an Unbalanced Wheatstone Bridge?

One limitation of an Unbalanced Wheatstone Bridge is that it requires a known resistor to be present in the circuit, which may not always be available. Additionally, small changes in resistance may not be accurately measured due to the sensitivity of the bridge. Finally, the bridge may become unbalanced due to external factors such as temperature changes or electrical interference, leading to inaccurate measurements.

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