Wheatstone Bridge Sensitivity Quiz and Flashcards

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Questions and Answers

What is the effect of arm resistance on the sensitivity of a Wheatstone bridge?

It has no effect on the sensitivity

It decreases the sensitivity (correct)

It is dependent on the source voltage

It increases the sensitivity

What is the purpose of decreasing the arm resistance ratio in a Wheatstone bridge?

To increase the accuracy of the measurement

To decrease the range of the instrument

To increase the linearity of the instrument

To increase the sensitivity of the measurement (correct)

What is the definition of sensitivity of measurement?

The precision of an instrument

The accuracy of an instrument

The range of an instrument

The change in instrument output per unit change in measured quantity (correct)

What is the purpose of increasing the source voltage in a Wheatstone bridge?

To increase the sensitivity of the measurement Signup and view all the answers

What is the term that describes an instrument's degree of freedom from random errors?

Precision Signup and view all the answers

What is the ratio between the maximum signal measured to the smallest part that can be resolved?

Resolution Signup and view all the answers

What is a desirable characteristic of an instrument's output reading?

Linearity Signup and view all the answers

What is the purpose of the reference temperature T0 in the thermistor equation?

To provide a reference point for temperature measurement Signup and view all the answers

What is the primary advantage of thermistors?

Rapid resistance change with small temperature changes Signup and view all the answers

What is a common application of thermistors in medical equipment?

Accurate temperature measurement Signup and view all the answers

Why are thermistors not suitable for wide operating temperature ranges?

Their resistance-temperature characteristic is non-linear Signup and view all the answers

What is the typical value of β in the thermistor equation?

4000 Signup and view all the answers

What is a common application of thermistors in home appliances?

All of the above Signup and view all the answers

What is the main advantage of thermistors in terms of size?

They are small in size Signup and view all the answers

What is a characteristic of thermistors that makes them suitable for portable applications?

Easy portability Signup and view all the answers

What is the primary purpose of thermistors in modern coffee makers?

To accurately measure and control water temperature Signup and view all the answers

Why are thermistors used in computers?

To monitor the CPU temperature Signup and view all the answers

Study Notes

Sensitivity of Wheatstone Bridge

The effect of arm resistance on sensitivity: arm resistance affects the sensitivity of the Wheatstone bridge
The effect of arm resistance ratio on sensitivity: arm resistance ratio also affects the sensitivity of the Wheatstone bridge
The effect of source voltage on sensitivity: source voltage affects the sensitivity of the Wheatstone bridge

Improving Sensitivity of Wheatstone Bridge

Decrease arm resistance to improve sensitivity
Decrease arm resistance ratio to improve sensitivity
Increase source voltage to improve sensitivity

Measurement Definitions

Sensitivity of measurement: a measure of the change in instrument output that occurs when the quantity being measured changes by a given amount
Accuracy: a measure of how close the output reading of the instrument is to the correct value
Precision: a term that describes an instrument's degree of freedom from random errors
Range or Span: the minimum and maximum values of a quantity that the instrument is designed to measure
Linearity: the output reading of an instrument is linearly proportional to the quantity being measured
Resolution: the ratio between the maximum signal measured to the smallest part that can be resolved

Sensor and Transducer

Sensor: a device that measures physical quantities and converts them into an easily readable signal
Transducer: a device that converts a non-electrical signal into an electrical signal
Examples of sensors: barometer, accelerometer
Examples of transducers: thermocouple, thermistor

Thermistor

Definition: a type of resistor whose resistance changes rapidly with small changes in temperature
Working principle: resistance is dependent on temperature
Types of thermistors: NTC (Negative Temperature Co-efficient) and PTC (Positive Temperature Co-efficient)
NTC thermistors: resistance decreases with increasing temperature
PTC thermistors: resistance increases with increasing temperature
Relationship between resistance and temperature: governed by the expression RT = R0 * e^(-β/T)

Advantages and Disadvantages of Thermistors

Advantages:
- Rapid change in resistance with small change in temperature
- Low cost
- Small size
- Easy to transport
Disadvantages:
- Not suitable for wide operating range
- Non-linear resistance versus temperature characteristics

Applications of Thermistors

Medical equipment
3D printer hot ends
Home appliances (ovens, hair dryers, toasters, refrigerators)
Modern coffee makers
Computers
Temperature sensors

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Description

Learn about the factors that affect the sensitivity of a Wheatstone bridge, including arm resistance, arm resistance ratio, and source voltage. Discover how to improve the sensitivity of this measurement tool.