Sensors and Measurement Quiz

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Questions and Answers

What is the primary function of a charge-coupled device (CCD)?

To measure pressure variations.

To detect magnetic fields.

To measure temperature changes in materials.

To capture digital images. (correct)

Which of the following is NOT one of the basic types of temperature measurement sensors?

Piezoelectric sensors (correct)

Infrared radiators

Resistive temperature devices (RTDs)

Thermocouples

How do inductive sensors determine the distance to their target?

By assessing electronic resistance.

By detecting alterations in a magnetic field. (correct)

By using changes in capacitance.

By measuring changes in light reflection.

What is a common characteristic shared by different types of temperature measuring sensors?

They all measure temperature through changes in a physical characteristic. Signup and view all the answers

What distinguishes capacitive sensors from inductive sensors?

Capacitive sensors use changes in capacitance, whereas inductive sensors use changes in magnetic fields. Signup and view all the answers

What is the primary purpose of ANOVA in statistical analysis?

To test for significant differences among multiple samples Signup and view all the answers

Which statement best describes the coefficient of determination, R-squared (R²)?

It indicates how well a model fits data and predicts outcomes. Signup and view all the answers

In the context of regression analysis, when is R-squared equal to 0?

When the model cannot predict the outcome better than the average value Signup and view all the answers

What does a pixel represent in a digital image?

The smallest unit of a digital image or graphic Signup and view all the answers

Which of the following best describes a photon?

A bundle of electromagnetic energy that makes up light Signup and view all the answers

What is typically indicated by higher R-squared values in regression analysis?

A better fit of the model to the data Signup and view all the answers

Which type of ANOVA would you use to test the effect of two independent variables on a dependent variable?

Two-Way ANOVA Signup and view all the answers

What is the relationship between resolution and megapixels in digital imaging?

Resolution represents pixel dimensions, not pixel count. Signup and view all the answers

Study Notes

Engineering Measurements - Final Exam Prep

ANOVA (Analysis of Variance): A statistical test used to determine if there are statistically significant differences between more than two samples.
Types of ANOVA: One-Way ANOVA and Two-Way ANOVA
One-Way ANOVA Hypothesis: Tests if a person's place of residence influences their salary. The null hypothesis (H₀) states that the mean salary is the same for all groups, while the alternative hypothesis (H₁) states that there are differences in mean values among groups.
Two-Way ANOVA Hypothesis: Tests if a person's place of residence and gender affect their salary. The null hypotheses (H₀) test for no difference in means between groups in each factor, and if one factor has no bearing on the other. The alternative hypotheses (H₁) states there are significant differences in the means, and one factor affects the others.

Regression Analysis

Simple statistical method to understand and quantify the relationship between variables.
Used to estimate one dependent variable based on the values of one or more independent variables.

Regression Equation

Method #3: Simple Linear Regression (example data provided)
Shows relationship between digital ads and revenue using a formula (y=78.075x+7930.4, R=0.9327, with a graph displaying the trend).

Coefficient of determination (R²)

Statistical measure indicating how well a model fits data and predicts outcomes.
R² values range from 0 to 1.
R² = 0: Model cannot predict better than using the average.
R² between 0 and 1: Model can partially predict the outcome.
R² = 1: Model can perfectly predict the outcome.

Chapter 2 - Data Types

Integer: Whole numbers, no decimals. (-707, 0, 707)
Floating Point: Numbers with decimal points. (707.07, 0.7, 707.00)
Array: Ordered collection of elements of the same data type.
String: Sequence of characters.
Boolean Operators: Used for complex searches, such as "and," "or," and "not".

Choosing a Data Acquisition System

Technical Considerations: What types of analog/digital signals and data need measuring? What resolution, accuracy and noise performance is needed? Does the system need isolation, filtering or anti-aliasing? How fast does the data need to be acquired? Is it a portable, benchtop, or rack-mounted system?
Ease of Use, Features, and Support: Are operation manuals available and easy to read? What technical support is available? Is the user interface easy to learn? Can data be saved? Can analysis be done on the system or offline?

Investment Cost and Cost of Ownership Considerations

Software inclusion and updates, annual maintenance fees. Calibration costs. Warranty period. Access to and cost of technical support.

Data Acquisition System Choices

Traditional versus virtual instrument options
Vendor-defined to user-defined approaches.
Factors like cost, functionality, and portability.

Data Acquisition Software Choices

Software criteria for data acquisition hardware interfacing.
Options include C, C++, C#, VB, Java, NI LabVIEW, DASYLab, and MATLAB.

Chapter 3 - Image Measurement

Photon: Fundamental unit of electromagnetic energy.
Pixel: Smallest unit of a digital image, forming a grid.
Properties of Photons: Zero Mass, no electrical charge, and stable. They carry energy based on frequency, and interact with other particles.

Chapter 3 - Imaging Techniques

Various imaging techniques (e.g., surface characteristics, brightness, temperature, soft X-ray imaging, thermal imaging, bioluminescence) and how they are utilized and work
Component parts of digital imaging systems (e.g., cameras, light sources, data acquisition & processing units).

Chapter 3 - Resolution vs Mega Pixels

Resolution describes number of pixels. Megapixels represent the total number of pixels.
CCD: Charge-coupled device, a major technology in digital imaging.
CMOS: Complementary Metal-Oxide Semiconductor, another technology in digital imaging.

Chapter 3 - Types of CMOS Image Sensors

Passive-pixel and active-pixel sensors.
Differences in noise, pixel size, and image processing.

Chapter 3 - CCD vs CMOS

Comparison of CCD and CMOS image sensors based on resolution, frame rate, noise, responsivity, color depth, and cost.

Chapter 4 - Accelerometer

A device to measure acceleration (rate of velocity change).
Measurement is in meters per second squared (m/s²) or in G-forces (g).
Practical uses in sensing vibrations and for orientation applications.
Types of accelerometers such as Piezoelectric, Capacitive and Piezo-resistive.

Chapter 5 - Temperature Sensor

Temperature: Defined as the energy level of matter
Different types of temperature sensors include: thermocouples, resistive temperature devices (RTDs), infrared, bimetallic, liquid expansion devices, molecular change of state and vibrating wire.

Chapter 5 - Thermocouples

Voltage devices. Output voltage increases with temperature changes.
Protection from the environment through shielding and coatings (e.g., Teflon)

Chapter 5 - Resistive Temperature Measuring Devices (RTDs) / Thermistors

Electrical devices, measuring in response to changes in resistance.
RTDs provide linear output (more stable). Thermistors are semiconductor-based devices with a nonlinear response.

Chapter 5 - Infrared Sensors

Infrared (IR) thermometers measure surface temperature without physical contact.
They work based on infrared radiation emitted by objects, which is proportional to temperature.

Chapter 5 - Bimetallic Devices

Devices that use expansion in metals to measure temperature, based on relative differences in expansion rates.

Chapter 5 - Thermometers (Mercury / Liquid Expansion)

Liquid expansion in response to temperature changes.
Specific types include mercury thermometers and organic liquid devices (often red colored).

Chapter 5 - Change-of-State Sensors

Devices show a change of state in response to a change in temperature.
Practical uses include confirmation of temperature not exceeding a certain level.

Chapter 5 - Silicon Diode Temperature Sensors

Linear devices for low cryogenic temperatures.
Voltage changes in response to changes in temperatures.

Chapter 5 - Vibrating Wire Temperature Sensors

Highly accurate temperature sensors, particularly for measuring temperatures in water, soil, or concrete

Chapter 6 - Strain Gauge

Measures strain - the change in an object's length or shape due to force.
It's a uniaxial transducer with a wire grid measuring resistance change.
Types include: Thin resistive wire, Active Length, Measuring Grid Area, and Transverse Length

Chapter 6 - Strain Gauge Measurement Principles

Resistance-wire principle: relating resistance changes in a wire to its length and cross-sectional area.
Gauge factor: relationship between the change in resistance and the strain.

Chapter 6 - Wheatstone Bridge

Measuring circuit for small resistance changes.
Measures very small changes in voltage, which is proportional to the amount of strain.

Chapter 7 - Humidity Sensor

Measures moisture content in the air.
Different types: Capacitive, resistive, thermal conductivity, and optical.

Chapter 7 - Capacitive Humidity Sensors

Electrical capacitance based.
Two metal electrode layers with a dielectric layer absorb incoming moisture, causing a voltage change.

Chapter 7 - Resistive Humidity Sensors

Measured based on the change in the material’s electrical resistance when in the presence of moisture.
The output voltage is inversely proportional to relative humidity.

Chapter 7 - Thermal Conductivity Humidity Sensors

Measures absolute humidity based on the change in conductivity in dry air vs. humid air using two thermistors, one exposed & the second encapsulated

Chapter 7 - Optical Humidity Sensors

Sensors use light to measure humidity by detecting changes in light absorption or reflection corresponding to the humidity levels.

Chapter 8 - Displacement, Position and Proximity Sensors

Displacement: Measures amount of movement
Position: Measures position in relation to a reference point
Proximity: Detects how close an object is.
Types of sensors: Potentiometer/ resistive, ultrasonic, laser, inductive and capacitive

Chapter 8 - Potentiometer/ Resistive Displacement Sensors

Converts a physical movement into a change in resistance.
Commonly used for volume and tuning controls in some equipment.

Chapter 8 - Ultrasonic Displacement Sensors

Based on the time of flight for ultrasonic signals.

Chapter 8 - Laser Sensors

Utilizes the time it takes for a pulse of laser light to reflect off an object to determine the distance to the target object.

Chapter 8 - Inductive vs. Capacitive Displacement Sensors

Inductive: based on changes in a magnetic field
Capacitive: based on changes in capacitance.

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Description

Test your knowledge on various sensors and their functions, including charge-coupled devices (CCDs) and temperature measurement sensors. This quiz covers the principles behind inductive and capacitive sensors as well as their characteristics. Perfect for students studying electronics and measurement technologies.