The bridge most suited for measurement of a four-terminal resistance in the range of 0.001 Ω to 0.1 Ω is
- AWien’s bridge
- BKelvin double bridge
- CMaxwell’s bridge
- DSchering bridge
Solution & Step-by-step Explanation
Understanding Low Resistance Measurement
Measuring very low resistances, especially those in the range of 0.001 Ω to 0.1 Ω, presents a unique challenge. Standard resistance measurement techniques can be inaccurate because the resistance of the connecting wires and contact points can become significant compared to the resistance being measured. These extra resistances add errors to the measurement. Therefore, a specialized bridge circuit is required to overcome this issue.
Suitability of Kelvin Double Bridge
The Kelvin double bridge is specifically designed for the accurate measurement of low resistances. Its key advantage lies in its four-terminal measurement capability:
- It uses separate pairs of connections for carrying the current and measuring the voltage drop across the resistance.
- This configuration effectively eliminates the errors caused by the resistance of the connecting leads and contact resistances at the terminals of the unknown low resistance.
- By minimizing the influence of these parasitic resistances, the Kelvin double bridge provides highly accurate readings for resistances in the milliohm range, making it the most suitable choice for the specified range of 0.001 Ω to 0.1 Ω.
Analysis of Other Bridge Options
The other bridges mentioned are designed for different types of measurements:
- Wien’s bridge: Primarily used for measuring frequency and determining the properties of capacitors. It is not suitable for resistance measurements, especially low resistances.
- Maxwell’s bridge: Commonly used for measuring inductance. It compares an unknown inductance with standard capacitance and resistance.
- Schering bridge: Used for measuring capacitance and the dissipation factor (or loss angle) of capacitors and insulators.
Since these bridges are not designed to handle the complexities of low resistance measurement, they are inappropriate for the given task.
Measuring very low resistances, especially those in the range of 0.001 Ω to 0.1 Ω, presents a unique challenge. Standard resistance measurement techniques can be inaccurate because the resistance of the connecting wires and contact points can become significant compared to the resistance being measured. These extra resistances add errors to the measurement. Therefore, a specialized bridge circuit is required to overcome this issue.
Suitability of Kelvin Double Bridge
The Kelvin double bridge is specifically designed for the accurate measurement of low resistances. Its key advantage lies in its four-terminal measurement capability:
- It uses separate pairs of connections for carrying the current and measuring the voltage drop across the resistance.
- This configuration effectively eliminates the errors caused by the resistance of the connecting leads and contact resistances at the terminals of the unknown low resistance.
- By minimizing the influence of these parasitic resistances, the Kelvin double bridge provides highly accurate readings for resistances in the milliohm range, making it the most suitable choice for the specified range of 0.001 Ω to 0.1 Ω.
Analysis of Other Bridge Options
The other bridges mentioned are designed for different types of measurements:
- Wien’s bridge: Primarily used for measuring frequency and determining the properties of capacitors. It is not suitable for resistance measurements, especially low resistances.
- Maxwell’s bridge: Commonly used for measuring inductance. It compares an unknown inductance with standard capacitance and resistance.
- Schering bridge: Used for measuring capacitance and the dissipation factor (or loss angle) of capacitors and insulators.
Since these bridges are not designed to handle the complexities of low resistance measurement, they are inappropriate for the given task.