ME345W Final Exam Practice

Question 1

Readability

Answer 1

Closeness of Scale

Question 2

Least Count

Answer 2

Smallest Difference that can be detected

Question 3

Accuracy

Answer 3

Deviation of a reading from a known input stated as % of full scale

Question 4

Precision

Answer 4

Repeatability, Ability to reproduce a certain reading with a given accuracy

Question 5

Calibration

Answer 5

Test, Check, Compare the instrument against known standard data

Question 6

Resolution

Answer 6

The smallest unit of the quantity under measurement which can be reliably detected

Question 7

Accuracy Error

Answer 7

-Closeness of the average reading to the true value
-The value of one reading minus the true value

Question 8

Precision Error

Answer 8

The value of one reading minus the average of readings

Question 9

Significant Digits

Answer 9

Digits that are relevant and meaningful

Question 10

NIST

Answer 10

National Institute for Standards and Technology

Question 11

Three Staged of Sensors

Answer 11

1) Detector
2) Intermediate Stage (Amplify, Filter)
3) Final/Terminating

Question 12

3 Sources of Noise in the Measurement System

Answer 12

1) Environment
2) Electrical Signal Conditioning System
3) Quantization

Question 13

Static

Answer 13

Constant in Time

Question 14

Dynamic

Answer 14

Varying in time

Question 15

Analog

Answer 15

Signal is analogous to a continues physical process

Question 16

Digital

Answer 16

Signal is a set of discrete numbers

Question 17

Rise Time

Answer 17

Time from 90% to 10% of the known value

Question 18

Setting Time

Answer 18

Time for it to reach Steady-State Response

Question 19

Low Pass Filter

Answer 19

Low frequency signals will pass

Question 20

High Pass Filter

Answer 20

High frequency signals will pass

Question 21

Full Scale

Answer 21

Final-Initial Value

Question 22

Cyclic TIme

Answer 22

Time to arrive Steady-State Solution

Question 23

Hysteresis

Answer 23

Difference in the response of increasing/decreasing PV

Question 24

Calibration is the process of checking the rest of the date against the mean (True or False)

Answer 24

False

Question 25

It can be estimated with reasonable accuracy that the system (sensor) arrives at its final reading after a period that is double its rise time. (True or False)

Answer 25

False

Question 26

The quantization error is a dynamic error, and it results from the digital to analog converter used in the data acquisition system.

Answer 26

False

Question 27

Obstruction Flow Meter

Answer 27

-An instrument that measures flow rate by a reduction of cross-sectional area which causes a pressure drop

Question 28

3 most common types of obstruction flow meters

Answer 28

1) Venture (smallest headloss/most accurate) 2) flow nozzle (medium/medium) 3) Orifice (highest headloss/least accurate)

Question 29

Pitot Tube

Answer 29

-A pressure differential flow speed measurement instrument

Question 30

Rotameter

Answer 30

-An instrument that measures flow rate using the concepts of buoyancy force, drag force, and weight

Question 31

Rotor/Turbine flow meter

Answer 31

-An instrument that allows a fluid to flow through blades to measure the flow rate

Question 32

Paddle Flow meter

Answer 32

-An instrument that allow fluid to flow over a paddle wheel to measure the flow rate

Question 33

Electromagnetic flowmeter

Answer 33

-An instrument that measures the flow rate of conductive liquids

Question 34

Vortex Flow meter

Answer 34

An instrument that uses the concept of vortex shedding to measure the flow rate

Question 35

Wheatstone Bridge

Answer 35

Typically used to measure the change in resistance from 1 ohm to 1 Mohm 1) balanced: typically used to find output resistance of transducers 2) unbalanced: typically used to find dynamic frequencies

Question 36

unbounded strain gage

Answer 36

-A strain gage that the wire is not cemented to a structure -can find acceleration -measures strain

Question 37

bounded strain gage

Answer 37

-A strain gage that the wires is cemented to a structure Measures strain

Question 38

Rosette strain gage

Answer 38

-A strain gage used for complicated geometries -three directions are needed (45 degrees)

Question 39

How to account for temperature change in a strain gage

Answer 39

-You can account for temperature change by having two strain gages. One goes on top and another goes on the bottom. The one on top acts as a thermal insulator

Question 40

Frequency response of a bonded strain gage is dependent

Answer 40

on the mechanical properties of the structure which it is bonded

Question 41

Power excitation voltage is limited by the

Answer 41

power dissipation and hating resistances

Question 42

Strain sensitivity

Answer 42

The amount of deformation that can be indicated by the gage per unit length