Measurement of Low Resistance by Kelvin's Double Bridge Method Problem No 1

TL;DR

This video demonstrates how to calculate the value of an unknown resistance using Kelvin's double bridge method.

Transcript

hello friends in this video we are going to solve a problem based on the measurement of resistance using kelvin's double bridge method so let us start with a problem so our question is that a four terminal resistor of approximately 50 micro ohm resistance is measured by using a kelvin bridge which is having the following component resistances now t... Read More

Key Insights

• 🍻 Kelvin's double bridge method compensates for the resistance of the connecting link to achieve accurate resistance measurements.
• 🌉 The formula used to calculate the unknown resistance is derived from the Wheatstone bridge.
• 🌉 The accuracy of the measurement depends on the value of the standard resistor and the precision of the resistors in the bridge circuit.
• 🥳 Both inner and outer ratio arms play a crucial role in balancing the bridge circuit for accurate measurements.

Questions & Answers

Q: What is the purpose of using Kelvin's double bridge method in resistance measurement?

Kelvin's double bridge method is used to achieve accurate resistance measurements by compensating for the resistance of the connecting link, which may affect the accuracy of the results.

Q: How does the value of the standard resistor affect the measurement accuracy?

The value of the standard resistor is crucial for accurate measurements. A lower value can lead to higher accuracy, but it should still be within the range of the unknown resistance being measured.

Q: What is the significance of the outer and inner ratio arms in the Kelvin bridge circuit?

The outer and inner ratio arms help create a balanced bridge circuit by adjusting the resistances. They play a crucial role in obtaining accurate measurements of the unknown resistance.

Q: How can the measurement accuracy be improved in Kelvin's double bridge method?

To improve accuracy, one can use higher precision resistors for the components and ensure proper calibration of the bridge circuit. Additionally, reducing the resistance of the connecting link can minimize measurement errors.

Summary & Key Takeaways

• The video explains how to solve a problem involving the measurement of resistance using Kelvin's double bridge method.

• It provides the values of different resistances in the Kelvin bridge circuit, including the standard resistor, inner and outer ratio arms, and the resistance of the connecting link.

• By applying the formula derived from the Wheatstone bridge, the unknown resistance is calculated to be 49.97 micro-ohms.