Why Use Sense Resistors in 4-Wire Kelvin Measurements?

Thread starter Tweedle_Dee
Start date Jul 1, 2010
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Kelvin Measurements Resistors

In summary, sense resistors are used in 4-wire Kelvin measurements to minimize the effects of lead resistance and ensure accurate measurement of the device under test. They work by creating a voltage drop proportional to the current passing through them, allowing for more precise and reliable measurements. The main benefits of using sense resistors include increased accuracy, higher current capabilities, and prevention of excessive heat. While not necessary for all 4-wire Kelvin measurements, they are typically used when measuring low resistance values or when high accuracy is required. When choosing a sense resistor, factors such as the desired measurement accuracy, resistance value of the device under test, and maximum current should be considered. Additionally, the power rating of the sense resistor should be evaluated to ensure it

Jul 1, 2010

Tweedle_Dee

In a 4-wire (kelvin) measuring system, why are there "sense" resistors? I understand that because there is very little current on the sense line there is no voltage drop. What purpose do they serve?

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Jul 1, 2010

waht

Where are the sense resistors exactly? In a Kelvin 4-probe you run a constant current through a test resistance and then measure voltage drop across it.

Related to Why Use Sense Resistors in 4-Wire Kelvin Measurements?

1. Why are sense resistors used in 4-wire Kelvin measurements?

Sense resistors are used in 4-wire Kelvin measurements to minimize the effects of lead resistance and ensure accurate measurement of the device under test. They provide a separate path for the measurement current, reducing errors caused by voltage drops in the measurement leads.

2. How do sense resistors work in 4-wire Kelvin measurements?

Sense resistors work by creating a voltage drop proportional to the current passing through them. This voltage drop is then measured and used to calculate the resistance of the device under test, without interference from lead resistances.

3. What are the benefits of using sense resistors in 4-wire Kelvin measurements?

The main benefit of using sense resistors is the increased accuracy of the measurement. By minimizing lead resistance effects, the measurement is more precise and reliable. Sense resistors also allow for higher currents to be used without creating excessive heat, which can affect the accuracy of the measurement.

4. Are sense resistors necessary for all 4-wire Kelvin measurements?

No, sense resistors are not always necessary for 4-wire Kelvin measurements. They are typically used when high accuracy is required or when measuring low resistance values. For higher resistance values, the effects of lead resistance are negligible and sense resistors may not be needed.

5. How do I choose the right sense resistor for my 4-wire Kelvin measurements?

The choice of sense resistor depends on the specific requirements of your measurement. Factors to consider include the desired measurement accuracy, the resistance value of the device under test, and the maximum current that can be safely used. It is also important to consider the power rating of the sense resistor to ensure it can handle the expected current without overheating.