Exam 2 definitions

Question 1

Thermocouple

Answer 1

-An instrument that measures temperature
-A junction of two dissimilar metals
-Sensitivity V/C
-EMF generated due to a change in temperature

Question 2

RTD(Resistance Temperature Detector)

Answer 2

-An instrument that measures temperature
-Made of platinum
-Sensitivity deltaR/DeltaT

Question 3

Thermistor

Answer 3

-An instrument that measures resistance
-Tempco
-Made of metal oxide semiconductor
-A temperature sensitive Resistor
-Very High sensitivity

Question 4

Bimetallic Thermometer

Answer 4

-An instrument that measures temperature
-Made of a strip of two dissimilar metals
-Functions because of the coefficient of thermal expansions of two metals
-Mechanical Temperature Sensor

Question 5

Thermometer

Answer 5

-An instrument that measures temperature
-Uses the coefficient of thermal expansion of a liquid(typically Mercury) to measure temperature
-Mechanical Temperature Sensor

Question 6

Obstruction Flow meter

Answer 6

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

Question 7

3 most common types of obstruction flow meters

Answer 7

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

Question 8

Pitot Tube

Answer 8

-A pressure differential flow speed measurement instrument

Question 9

Rotameter

Answer 9

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

Question 10

Rotor/Turbine flow meter

Answer 10

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

Question 11

Paddle Flow meter

Answer 11

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

Question 12

Electromagnetic flowmeter

Answer 12

-An instrument that measures the flow rate of conductive liquids

Question 13

Vortex Flow meter

Answer 13

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

Question 14

Wheatstone Bridge

Answer 14

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 15

bounded strain gage

Answer 15

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

Question 16

bounded strain gage

Answer 16

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

Question 17

Rosette strain gage

Answer 17

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

Question 18

How to account for temperature change in a strain gage

Answer 18

-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 19

Frequency response of a bonded strain gage is dependent

Answer 19

on the mechanical properties of the structure which it is bonded

Question 20

Power excitation voltage is limited by the

Answer 20

power dissipation and hating resistances

Question 21

Strain sensitivity

Answer 21

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