Temperature sensors can measure temperature through various methods like thermocouples, resistance temperature detectors (RTDs), and thermistors. Thermocouples generate small voltages based on the temperature difference between two junctions of dissimilar metals. RTDs measure the change in electrical resistance of metals like platinum as temperature varies, while thermistors use semiconductors that exhibit large changes in resistance with temperature. The document discusses the construction, properties, and operating principles of these common temperature sensor types.
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We provide you Project Temperature Sensors – Types.You can choose the best of your choice and interest from the list of topics we suggested. All new project ideas that are appearing focuses to improve the knowledge of Engineering students.
https://www.elprocus.com
Visit our page to get more ideas on Project Report Format for Final Year Engineering Students these ideas developed by professionals.
Elprocus provides free verified electronic projects kits around the world with abstracts, circuit diagrams, and free electronic software. We provide guidance manual for Do It Yourself Kits (DIY) with the modules at best price along with free shipping.
This Presentation can be used by the Students of Engineering who Deals with the Subject INDUSTRIAL INSTRUMENTATION and use it for Refrence (Anyways you Guys will Copy Paste or Download it) ;)
This Course basics of instrumentation and control systems used in oil and gas and petrochemical industry,
The course the following topics
Basics of Instrumentation
Field Instruments
Control Valves
Process Control
Control systems
esistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum, nickel, or copper. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes.
Resistance thermometers are constructed in a number of forms and offer greater stability, accuracy and repeatability in some cases than thermocouples. While thermocouples use the Seebeck effect to generate a voltage, resistance thermometers use electrical resistance and require a power source to operate. The resistance ideally varies nearly linearly with temperature per the Callendar–Van Dusen equation.
The platinum detecting wire needs to be kept free of contamination to remain stable. A platinum wire or film is supported on a former in such a way that it gets minimal differential expansion or other strains from its former, yet is reasonably resistant to vibration. RTD assemblies made from iron or copper are also used in some applications. Commercial platinum grades exhibit a temperature coefficient of resistance 0.00385/°C (0.385%/°C) (European Fundamental Interval).[7] The sensor is usually made to have a resistance of 100 Ω at 0 °C. This is defined in BS EN 60751:1996 (taken from IEC 60751:1995). The American Fundamental Interval is 0.00392/°C,[8] based on using a purer grade of platinum than the European standard. The American standard is from the Scientific Apparatus Manufacturers Association (SAMA), who are no longer in this standards field. As a result, the "American standard" is hardly the standard even in the US.
Lead-wire resistance can also be a factor; adopting three- and four-wire, instead of two-wire, connections can eliminate connection-lead resistance effects from measurements (see below); three-wire connection is sufficient for most purposes and is an almost universal industrial practice. Four-wire connections are used for the most precise applications.
Instrumentation and process control fundamentalshossam hassanein
Basic course covers:
-Basic understanding of process control
-Important process control terminology
-Major components of a process loop
-Instrumentation P&ID symbols
This article provides an introduction to the fundamental of Sensors and Transducers. It illustrates the different classifications of sensors and transducers. Explains capacitive, resistive and inductive transducers in brief. Also shows the examples under these types of transducers.
This Presentation can be used by the Students of Engineering who Deals with the Subject INDUSTRIAL INSTRUMENTATION and use it for Refrence (Anyways you Guys will Copy Paste or Download it) ;)
This Course basics of instrumentation and control systems used in oil and gas and petrochemical industry,
The course the following topics
Basics of Instrumentation
Field Instruments
Control Valves
Process Control
Control systems
esistance thermometers, also called resistance temperature detectors (RTDs), are sensors used to measure temperature. Many RTD elements consist of a length of fine wire wrapped around a ceramic or glass core but other constructions are also used. The RTD wire is a pure material, typically platinum, nickel, or copper. The material has an accurate resistance/temperature relationship which is used to provide an indication of temperature. As RTD elements are fragile, they are often housed in protective probes.
Resistance thermometers are constructed in a number of forms and offer greater stability, accuracy and repeatability in some cases than thermocouples. While thermocouples use the Seebeck effect to generate a voltage, resistance thermometers use electrical resistance and require a power source to operate. The resistance ideally varies nearly linearly with temperature per the Callendar–Van Dusen equation.
The platinum detecting wire needs to be kept free of contamination to remain stable. A platinum wire or film is supported on a former in such a way that it gets minimal differential expansion or other strains from its former, yet is reasonably resistant to vibration. RTD assemblies made from iron or copper are also used in some applications. Commercial platinum grades exhibit a temperature coefficient of resistance 0.00385/°C (0.385%/°C) (European Fundamental Interval).[7] The sensor is usually made to have a resistance of 100 Ω at 0 °C. This is defined in BS EN 60751:1996 (taken from IEC 60751:1995). The American Fundamental Interval is 0.00392/°C,[8] based on using a purer grade of platinum than the European standard. The American standard is from the Scientific Apparatus Manufacturers Association (SAMA), who are no longer in this standards field. As a result, the "American standard" is hardly the standard even in the US.
Lead-wire resistance can also be a factor; adopting three- and four-wire, instead of two-wire, connections can eliminate connection-lead resistance effects from measurements (see below); three-wire connection is sufficient for most purposes and is an almost universal industrial practice. Four-wire connections are used for the most precise applications.
Instrumentation and process control fundamentalshossam hassanein
Basic course covers:
-Basic understanding of process control
-Important process control terminology
-Major components of a process loop
-Instrumentation P&ID symbols
This article provides an introduction to the fundamental of Sensors and Transducers. It illustrates the different classifications of sensors and transducers. Explains capacitive, resistive and inductive transducers in brief. Also shows the examples under these types of transducers.
Resistance Temperature Detector
WHAT IS RTD ?
WHY IS RTD USED?
Typical Design
RTD PROBE
Common Resistance materials for RTD
Advantages of RTD
Application OF RTD
Question and Answers
Usage of Platinum
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
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Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
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CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
Democratizing Fuzzing at Scale by Abhishek Aryaabh.arya
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This keynote talks about the democratization of fuzzing at scale, highlighting the collaboration between open source communities, academia, and industry to advance the field of fuzzing. It delves into the history of fuzzing, the development of scalable fuzzing platforms, and the empowerment of community-driven research. The talk will further discuss recent advancements leveraging AI/ML and offer insights into the future evolution of the fuzzing landscape.
Event Management System Vb Net Project Report.pdfKamal Acharya
In present era, the scopes of information technology growing with a very fast .We do not see any are untouched from this industry. The scope of information technology has become wider includes: Business and industry. Household Business, Communication, Education, Entertainment, Science, Medicine, Engineering, Distance Learning, Weather Forecasting. Carrier Searching and so on.
My project named “Event Management System” is software that store and maintained all events coordinated in college. It also helpful to print related reports. My project will help to record the events coordinated by faculties with their Name, Event subject, date & details in an efficient & effective ways.
In my system we have to make a system by which a user can record all events coordinated by a particular faculty. In our proposed system some more featured are added which differs it from the existing system such as security.
COLLEGE BUS MANAGEMENT SYSTEM PROJECT REPORT.pdfKamal Acharya
The College Bus Management system is completely developed by Visual Basic .NET Version. The application is connect with most secured database language MS SQL Server. The application is develop by using best combination of front-end and back-end languages. The application is totally design like flat user interface. This flat user interface is more attractive user interface in 2017. The application is gives more important to the system functionality. The application is to manage the student’s details, driver’s details, bus details, bus route details, bus fees details and more. The application has only one unit for admin. The admin can manage the entire application. The admin can login into the application by using username and password of the admin. The application is develop for big and small colleges. It is more user friendly for non-computer person. Even they can easily learn how to manage the application within hours. The application is more secure by the admin. The system will give an effective output for the VB.Net and SQL Server given as input to the system. The compiled java program given as input to the system, after scanning the program will generate different reports. The application generates the report for users. The admin can view and download the report of the data. The application deliver the excel format reports. Because, excel formatted reports is very easy to understand the income and expense of the college bus. This application is mainly develop for windows operating system users. In 2017, 73% of people enterprises are using windows operating system. So the application will easily install for all the windows operating system users. The application-developed size is very low. The application consumes very low space in disk. Therefore, the user can allocate very minimum local disk space for this application.
Quality defects in TMT Bars, Possible causes and Potential Solutions.PrashantGoswami42
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Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
2. Temperature sensors - general
• Temperature sensors are deceptively simple
– Thermocouples - any two dissimilar materials, welded
together at one end and connected to a micro-voltmeter
– Peltier cell - any thermocouple connected to a dc source
– Resistive sensor - a length of a conductor connected to an
ohmmeter
• More:
• Some temperature sensors can act as actuators as well
• Can be used to measure other quantities (electromagnetic
radiation, air speed, flow, etc.)
• Some newer sensors are semiconductor based
3. Temperature sensors - types
• Thermoelectric sensors
– Thermocouples and thermopiles
– Peltier cells (used as actuators but can be used as sensors)
• Thermoresistive sensors and actuators
– Conductor based sensors and actuators (RTDs)
– Semiconductor based sensors - thermistors, diodes
• Semiconductor junction sensors
4. Thermoresistive sensors
• Two basic types:
– Resistive Temperature Detector (RTD)
• Metal wire
• Thin film
• Silicon based
– Thermistors (Thermal Resistor)
• NTC (Negative Temperature Coefficient)
• PTC (Positive Temperature Coefficient)
5. Resistance temperature detectors
• The resistance of most metal increases over limited
temperature range in reasonably linear way with
temperature
• Where Rt is resistance at a temperature t
• Ro is resistance at t=0 and αa constant for metal
termed the temperature coefficient of resistance
• RTDs are simple resistive element in the form of coil
of wire of such metals as platinium nickel copper
alloys
6. Thermoresistive effect
• Conductivity depends
on temperature
• Conductors and
semiconductors
• Resistance is
measured, all other
parameters must stay
constant.
R = L sS
7. Thermoresistive effect (cont.)
• Resistance of a length of
R = wire
sS
• Conductivity is:
s = s0
• Resistance as a function
1 + a T - T0
of temperature:
• a - Temperature
R T = L
s Coefficient of Resistance
0 S
(TCR) [C-1]
L 1 + a T - T 0
8. Thermoresistive effect (cont.)
• T is the temperature [°C ]
• s0 is the conductivity of the conductor at the
reference temperature T0.
• T0 is usually given at 20°C but may be given at
other temperatures as necessary.
• a - Temperature Coefficient of Resistance
(TCR) [C-1] given at T0
9. Temperature Coefficient of Resistance
Material Conductivity [S/m] Temperature Coefficint of
Resistance (TCR) C
Copper (Cu) 5.7-5.9 x 107 0.0039
Carbon (C) 3.0 x105 0.0005
Constantan (60%Cu,40%Ni) 2.0 x106 0.00001
Cromium (Cr) 5.6 x 106 0.0059
Germanium (Ge) 2.2 0.05
Gold (Au) 4.1 x 107 0.0034
Iron (Fe) 1.0 x 107 0.0065
Mercury (Hg) 1.0 x 106 0.00089
Nichrome (NiCr) 1.0 x 106 0.0004
Nickel (Ni) 1.15 x 107 0.0069
Platinum (Pl) 9.4 x 106 0.01042
Silicon (Si) (pure) 4.35 x 10-6 0.07
Silver (Ag) 6.1 x 107 0.0016
Titanium (Ti) 1.8 x 106 0.042
Tungsten (W) 1.8 x 107 0.0056
Zinc (Zn) 1.76 x 107 0.0059
Aluminum (Al) 3.6 x 107 0.0043
Note: Instead of conductivity [S/m], some sources list resistivity , measured in ohm.meter =
1/ [ m). 1S/m=1/ m
10. Other considerations
• Tension or strain on the wires affect resistance
• Tensioning a conductor, changes its length and cross-sectional
area (constant volume)
– has exactly the same effect on resistance as a change in
temperature.
– increase in strain on the conductor increases the
resistance of the conductor (strain gauge)
• Resistance should be relatively large (25W and up)
11. Construction - wire RTD
• A spool of wire (length)
– Similar to heating elements
– Uniform wire
– Chemically and dimensionally stable in the sensing range
– Made thin (<0.1mm) for high resistance
• Spool is supported by a glass (pyrex) or mica support
– Similar to the way the heating element in a hair drier is supported
– Keeps strain at a minimum and allows thermal expansion
– Smaller sensors may not have an internal support.
• Enclosed in a glass, ceramic or metal enclosure
– Length is from a few cm, to about 50cm
13. Construction (cont.)
• Materials:
• Platinum - used for precision applications
– Chemically stable at high temperatures
– Resists oxidation
– Can be made into thin wires of high chemical purity
– Resists corrosion
– Can withstand severe environmental conditions.
– Useful to about 800 °C and down to below –250°C.
– Very sensitive to strain
– Sensitive to chemical contaminants
– Wire length needed is long (high conductivity)
14. Construction (cont.)
• Materials:
• Nickel and Copper
– Less expensive
– Reduced temperature range (copper only works up to about
300°C)
– Can be made into thin wires of high chemical purity
– Wire length needed is long (high conductivity)
– Copper is not suitable for corrosive environments (unless
properly protected)
– At higher temperatures evaporation increases resistance
15. Self heat in RTDs
• RTDs are subject to errors due to rise in their
temperature produced by the heat generated in
them by the current used to measure their resistance
• Wire wound or thin film
• Power dissipated: Pd=I2R ( I is the current (RMS) and R
the resistance of the sensor)
• Self heat depends on size and environment
• Given as temperature rise per unit power (°C/mW)
• Or: power needed to raise temperature (mW/ °C)
16. Self heat in RTDs (cont.)
• Errors are of the order of 0.01°C/mW to
10°C/mW (100mW/°C to 0.1mW/°C)
• Given in air and in water
– In water values are lower (opposite if mW/°C used)
• Self heat depends on size and environment
– Lower in large elements, higher in small elements
– Important to lower the current as much as possible
17. Response time in RTDs
• Response time
• Provided as part of data sheet
• Given in air or in water or both, moving or stagnant
• Given as 90%, 50% (or other) of steady state
• Generally slow
• Wire RTDs are slower
• Typical values
– 0.5 sec in water to 100 sec in moving air
18. Thermistors
• Are small pieces of materials made from
mixture of metal oxides such as chromium
cobalt iron manganese, and nickel
• Thermistors: Thermal resistor
• Became available: early 1960’s
• Based on oxides of semiconductors
– High temperature coefficients
– NTC
– High resistances (typically)
19. Thermistors (cont.)
• Transfer function:
• K [W] and b [°K] are constants
• R(T): resistance of the device
• T: temperature in °K
• Relation is nonlinear but:
– Only mildly nonlinear (b is small)
– Approximate transfer function
22. Thermistors - properties
• Most are NTC devices
• Some are PTC devices
• PTC are made from special materials
– Not as common
– Advantageous when runaway temperatures are
possible
23. Thermistors - properties
• Self heating errors as in RTDs but:
– Usually lower because resistance is higher
– Current very low (R high)
– Typical values: 0.01°C/mW in water to 1°C/mW in air
• Wide range of resistances up to a few MW
• Can be used in self heating mode
– To raise its temperature to a fixed value
– As a reference temperature in measuring flow
• Repeatability and accuracy:
– 0.1% or 0.25°C for good thermistors
24. Thermistors - properties
• Temperature range:
– - 50 °C to about 600 °C
– Ratings and properties vary along the range
• Linearity
– Very linear for narrow range applications
– Slightly nonlinear for wide temperature ranges
• Available in a wide range of sizes, shapes and also as probes
of various dimensions and shapes
• Some inexpensive thermistors have poor repeatability - these
must be calibrated before use.
25. Thermoelectric sensors
• Among the oldest sensors (over 150 years)
• Some of the most useful and most common
• Passive sensors: they generate electrical emfs
(voltages) directly
– Measure the voltage directly.
– Very small voltages - difficult to measure
– Often must be amplified before interfacing
– Can be influenced by noise
26. Thermoelectric sensors (cont.)
• Simple, rugged and inexpensive
• Can operate on almost the entire range of
temperature from near absolute zero to about
2700°C.
• No other sensor technology can match even a
fraction of this range.
• Can be produced by anyone with minimum skill
• Can be made at the sensing site if necessary
27. Thermoelectric sensors (cont.)
• Only one fundamental device: the thermocouple
• There are variations in construction/materials
– Metal thermocouples
– Thermopiles - multiple thermocouples in series
– Semiconductor thermocouples and thermopiles
– Peltier cells - special semiconductor thermopiles used as
actuators (to heat or cool)
28. Themocouple - analysis
• Conductors a, b
homogeneous
• Junctions at
temperatures T2 and T1
• On junctions 1 and 2:
• Total emf:
emfA = aA T2 - T1 emfB = aB T2 - T1
emfT = emfA - emfB = aA - aB T2 - T1 = aAB T2 - T1
29. Thermocouple - analysis
• aA and aB are the absolute Seebeck
coefficients given in mV/°C and are properties
of the materials A, B
• aAB=aA-aB is the relative Seebeck coefficient of
the material combination A and B, given in
mV/°C
• The relative Seebeck coefficients are normally
used.
31. Thermocouples - standard types
Table 3.4. Thermocouples (standard types and others) and some of their properties
Materials Sensitivity
[mV/°C]
at 25°C.
Standard
Type
designation
Temperature
range [°C]
Notes
Copper/Constantan 40.9 T -270 to 600 Cu/60%Cu40%Ni
Iron/Constantan 51.7 J -270 to
1000
Fe/60%Cu40%Ni
Chromel/Alumel 40.6 K -270 to
1300
90%Ni10%Cr/55%Cu45%Ni
Chromel/Constantan 60.9 E -200 to
1000
90%Ni10%Cr/60%Cu40%Ni
Platinum(10%)/Rhodium-Platinum 6.0 S 0 to 1450 Pt/90%Pt10%Rh
Platinum(13%)/Rhodium-Platinum 6.0 R 0 to 1600 Pt/87%Pt13%Rh
Silver/Paladium 10 200 to 600
Constantan/Tungsten 42.1 0 to 800
Silicon/Aluminum 446 -40 to 150
Carbon/Silicon Carbide 170 0 to 2000
Note: sensitivity is the relative Seebeck coefficient.
32. Seebeck coefficients - notes:
• Seebeck coefficients are rather small –
– From a few microvolts to a few millivolts per degree
Centigrade.
– Output can be measured directly
– Output is often amplified before interfacing to processors
– Induced emfs due to external sources cause noise
– Thermocouples can be used as thermometers
– More often however the signal will be used to take some
action (turn on or off a furnace, detect pilot flame before
turning on the gas, etc.)
33. Thermoelectric laws:
• Three laws govern operation of
thermocouples:
• Law 1. A thermoelectric current cannot be
established in a homogeneous circuit by heat
alone.
– This law establishes the need for junctions of
dissimilar materials since a single conductor is not
sufficient.
34. Thermoelectric laws:
Law 2. The algebraic sum of the thermoelectric forces
in a circuit composed of any number and
combination of dissimilar materials is zero if all
junctions are at uniform temperatures.
– Additional materials may be connected in the
thermoelectric circuit without affecting the output of the
circuit as long as any junctions added to the circuit are
kept at the same temperature.
– voltages are additive so that multiple junctions may be
connected in series to increase the output.
35. Thermoelectric laws:
• Law 3. If two junctions at temperatures T1 and T2
produce Seebeck voltageV2 and temperatures T2 and
T3 produce voltage V1, then temperatures T1 and T3
produce V3=V1+V2.
– This law establishes methods of calibration of
thermocouples.
36. Thermocouples: connection
• Based on the thermoelectric laws:
• Usually connected in pairs
– One junction for sensing
– One junction for reference
– Reference temperature can be lower or higher than sensing
temperature
37. Thermocouples (cont.)
• Any connection in the circuit between dissimilar
materials adds an emf due to that junction.
• Any pair of junctions at identical temperatures may
be added without changing the output.
– Junctions 3 and 4 are identical (one between material b
and c and one between material c and b and their
temperature is the same. No net emf due to this pair
– Junctions (5) and (6) also produce zero field
38. Thermocouples (cont.)
• Each connection adds two junctions.
• The strategy in sensing is:
• For any junction that is not sensed or is not a reference junction:
• Either each pair of junctions between dissimilar materials are
held at the same temperature (any temperature) or:
• Junctions must be between identical materials.
• Also: use unbroken wires leading from the sensor to the
reference junction or to the measuring instrument.
• If splicing is necessary to extend the length, identical wires must
be used to avoid additional emfs.
39. Connection without reference
• The connection to a voltmeter creates two junctions
– Both are kept at temperature T1
– Net emf due to these junctions is zero
– Net emf sensed is that due to junction (2)
– This is commonly the method used
40. Thermocouples - practical
considerations
• Choice of materials for thermocouples. Materials
affect:
– The output emf,
– Temperature range
– Resistance of the thermocouple.
• Selection of materials is done with the aid of three
tables:
– Thermoelectric series table
– Seebeck coefficients of standard types
– Thermoelectric reference table
41. Bimetal sensors
• Two metal strips welded together
• Each metal strip has different coefficient of
expansion
• As they expand, the two strips bend. This motion can
then be used to:
– move a dial
– actuate a sensor (pressure sensor for example)
– rotate a potentiometer
– close a switch
42. Bimetal sensors (cont.)
• To extend motion, the bimetal strip is bent into a
coil. The dial rotates as the coil expands/contracts
43. Bimetal sensors (cont.)
• Displacement for the
bar bimetal:
– r - radius of curvature
– T2 - sensed
temperature
– T1 - reference
temperature
(horizontal position)
– t - thickness of bimetal
bar
d = r 1 - cos 180L
pr m
r = 2t
3 au - al
T2 - T1
44. Bimetal switch (example)
• Typical uses: flashers in cars, thermostats)
• Operation
– Left side is fixed
– Right side moves down when heated
– Cooling reverses the operation