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Introduction to Transducers
Learning Module
Introduction
This booklet contains four units:
Pre-test (Knowledge Probe)
to
Introduction to Transducers Primary Knowledge (PK) unit
Transducers Activity – What are Transducers?
Final Assessment
Learning
This learning module is one of three SCME modules that discuss the types of components
foundModule
in microelectromechanical systems (MEMS). This module covers “transducers” –
what they are, how they work and how they are used in both macro and micro-sized
systems.
An contains
activity provides
further exploration into specific transducers and how they
This
booklet
four
are used units:
in everyday devices. Two related learning modules cover MEMS sensors and
actuators.
Pre-test (Knowledge
Probe)
Introduction to
Transducers
Primary
Target
audiences: High School, Community College, University
Knowledge (PK) unit
Activity – What are
MadeTransducers?
possible through grants from the National Science Foundation Department of Undergraduate
Education #0830384, 0902411, and 1205138.
Final Assessment
Any opinions, findings and conclusions or recommendations expressed in this material are those of the
authors
and creators,
andisdo not necessarily reflect the views of the National Science Foundation.
This
learning
module
one of three SCME
Center for Microsystems Education (SCME) NSF ATE Center
modules thatSouthwest
discuss the
© 2010 Regents of the University of New Mexico
types of components found
in microelectromechanical
Content is protected by the CC Attribution Non-Commercial Share Alike license.
systems (MEMS). This
module covers
Website: www.scme-nm.org
“transducers” – what they
are, how they work and
how they are used in both
macro and micro-sized
systems. An activity
provides further
Introduction to Transducers
Knowledge Probe
Participant Guide
Introduction
This learning module is one of three SCME modules that discuss the types of components found in
microelectromechanical systems (MEMS). This module covers “transducers” – what they are, how they
work and how they are used in both macro and micro-sized systems. An activity provides further
exploration into specific transducers and how they are used in everyday devices. Two related learning
modules cover MEMS sensors and actuators.
The purpose of this assessment is to determine your current understanding of transducers. This
knowledge leads to an understanding of applications and functions of transducers in microsystems
applications.
1. A thermocouple is a device that converts heat energy into electrical energy. A thermocouple is
a(n) ______________________.
a. sensor
b. transducer
c. actuator
d. transducer and actuator
2. Which of the following BEST describes a transducer? A device that
a. senses a change in its input and produces a readable output.
b. quantifies a change between an input and output.
c. converts one form of energy to another form of energy.
d. converts a change on the input into a proportional movement.
3. An electric motor converts electrical energy into rotary motion. An electric motor is a(n)
a. sensor
b. transducer
c. actuator
d. sensor and transducer
e. transducer and actuator
4. Which of the following BEST describes an electrochemical transducer?
a. Converts the energy from a chemical change or reaction to electrical energy.
b. Converts electrical energy into chemical energy seen either as a change or a reaction.
c. Converts motion or convection within a chemical into electrical energy.
d. Converts electrical energy into motion or convection within a chemical.
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Introduction to Transducers KP
5. Strain gauges, galvanometers, and generators are all what type of transducer?
a. Electrostatic
b. Electromechanical
c. Thermoelectric
d. Electromagnetic
6. Which of the following devices is an electrostatic transducer?
a. Cathode ray tube (CRT)
b. Incandescent light bulb
c. Comb drive
d. Hydrophone
7. Quartz crystal is a device that converts
a. mechanical stress into electrical energy
b. electrical energy into motion or movement
c. mechanical stress into heat
d. heat into motion or movement
8. One solution for long-lasting batteries in the micro-scale is to build a battery that consists of a
a. two-dimensional array of stacked, paper-thin flat electrodes.
b. two-dimensional array of low aspect ratio stacked carbon posts.
c. three-dimensional array of low aspect ratio carbon posts.
d. three-dimensional array of high aspect ratio carbon posts.
Support for this work was provided by the National Science Foundation's Advanced Technological
Education (ATE) Program through Grants. For more learning modules related to microtechnology,
visit the SCME website (http://scme-nm.org).
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Introduction to Transducers KP
Introduction to Transducers
Primary Knowledge
Participant Guide
Description and Estimated Time to Complete
This learning module is one of three SCME modules that discuss the types of components found in
microelectromechanical systems (MEMS). This module covers “transducers” – what they are, how
they work and how they are used in both macro and micro-sized systems. An activity provides
further exploration into specific transducers and how they are used in everyday devices. Two related
learning modules cover MEMS sensors and actuators.
In this lesson you will learn about transducers, what they are, what they can do, and various
applications. You will be asked to identify transducers in both the macro and micro scales. The
understanding of this information is important to microelectromechanical (MEMS) or microsystems
technology.
Estimated Time to Complete
Allow approximately 45 minutes to an hour to complete this lesson. This lesson consists of this
reading material and a short PowerPoint presentation that supports this lesson. You may view the
presentation before or after reading through this lesson.
Introduction
Three types of transducers: light bulb, microphone, and electric motors
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Introduction To Transducers
A transducer is any device that converts one form of energy into another. Examples of common
transducers include the following:
• A microphone converts sound into electrical impulses and a loudspeaker converts electrical
impulses into sound (i.e., sound energy to electrical energy and vice versa).
• A solar cell converts light into electricity and a thermocouple converts thermal energy into
electrical energy.
• An incandescent light bulb produces light by passing a current through a filament. Thus, a light
bulb is a transducer for converting electrical energy into optical energy.
• An electric motor is a transducer for conversion of electricity into mechanical energy or motion.
An actuator is a device that actuates or moves something. An actuator uses energy to provide
motion. Therefore, an actuator is a specific type of a transducer. Which of the previously mentioned
examples can function as an actuator?
Question:
Besides for the transducers mentioned here, what is another transducer found in your home?
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Introduction To Transducers
Transducers and sensors usually work hand-in-hand. Many sensors consist of a transducer and the
electronics needed to evaluate the transducer’s input and output. Therefore, a sensor can be defined
as a device that receives and responds to a signal. This signal is produced by some type of energy,
such as heat, light, motion, or chemical reaction that, in many cases, is the output from a transducer.
Once a sensor detects one or more of these signals (an input), it converts it into a readable
representation of the input signal. The output of the sensor could be a readable scale, an analog
readout or a digital readout. Based on this explanation of a sensor, you should see that sensors are
used in all aspects of life to detect and/or measure many different conditions.
Let’s take the example of a thermometer.
To the right are the images of both a
mercury thermometer and a digital
thermometer. The mercury thermometer
contains a small reservoir of mercury in
the tip. As the temperature of the
mercury increase, the mercury expands
and “moves up” the tube to a marking
that represents the temperature. The
digital thermometer uses a thermocouple
(which converts heat to voltage). The
varying voltage is used to indicate an
increase or decrease in temperature.
We’ll talk more about thermocouple
later. In both cases, energy is being converted by a transducer and then converted to a readable
output.
Question: What are some sensors that you are familiar with or use daily?
This lesson describes the basic concepts of transducers and introduces transducers in both the macro
and micro scales. The next lessons cover sensors and actuators.
Objectives
•
•
•
Define transducer.
Explain how two different types of transducers work.
Identify the micro equivalent of two macro-sized transducers.
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Introduction To Transducers
Key Terms (These terms are defined in the glossary at the end of this lesson.)
actuator
electroacoustic
electrochemical
electromagnetic
electromechanical
electrostatic
energy
mechanical
optical
photoelectric
sensors
transducer
Basic Concepts of Transducers
There are many variables which affect our everyday lives: speed of a car, velocity of the wind,
temperature of the oven, light level in the room. In most situations
these variables are continuously monitored. It is these variables that
are the feedback used to control the speed of a car, oven
temperatures, and light levels. The elements that sense these
variables and convert them to a different output energy are
transducers. Going back to the thermocouple, the thermocouple
“senses” an increase or decrease in temperature and outputs a voltage
proportional to the change in temperature. This “sensing” element
consists of two dissimilar metals joined together at one end into a
junction. When the junction of the two metals is heated or cooled, a
voltage is produced across the opposite ends of the metals. This effect
was discovered by Thomas Seebeck, and thus named the Seebeck
Effect or Seebeck coefficient. The voltage produced is representative
of the junction temperature. As the junction temperature increases,
the voltage increases proportionally and vice versa. This is an energy
conversion – temperature (heat energy) to voltage (electrical energy).
In summary, a transducer is a substance or a device that converts an
input energy into a different output energy. Because of this broad
definition, there are many devices that can be defined as transducers.
Such devices come in many varieties converting several different
types of energies. Following is a discussion of some of the more
common types of transducers.
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Introduction To Transducers
Electrochemical Transducers
Converting a Chemical Reaction to Electrical Energy (left: Fuel Cell, right: battery)
Electrochemical transducers convert the energy from a chemical change or reaction to electrical
energy and vice versa.
Some common electrochemical transducers include the following:
• pH probe – Converts chemical energy into an electrical energy
• Molecular electric transducer (MET) – Converts motion or convection in an electrolytic solution
into electrical energy
• Battery – Converts chemical energy directly into electrical energy
• Fuel cell – Converts the energy from a reaction within the fuel cell between oxygen and a fuel,
such as hydrogen, to electrical energy
• Galvanic Cells (also called electric batteries) – converts chemical reactions to electrical energy
Let’s take a closer look at the electrochemical battery illustrated above. This battery converts
chemical energy directly into electrical energy. A cathode and an anode typically of two dissimilar
metals are immersed in an electrolyte solution containing salts of their respective metals. A medium
(the salt bridge) separates the two electrodes, but allows ions to flow through the bridge from one
solution to the other. Due to the flow of ions between the two solutions a potential difference (or
voltage) is created. If a wire is placed connecting the two pieces of metals (the electrodes), current
flows. The amount of voltage developed across the cathode and the anode depends on the materials
that make up the battery.
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Introduction To Transducers
The fabrication of micro-sized batteries is a challenge but a challenge that needs to be met. Microsized sensors require micro-sized batteries in order to operate, especially when those sensors are
placed in remote areas such as the ocean floor or embedded below the surface of bridges and roads.
So how do you get a long-lasting battery from a device that is
smaller than the diameter of a strand of hair? “Traditional
batteries have a two-dimensional array of positive and negative
electrodes stacked on top of one another like sheets of paper.
Increasing battery power means adding more electrode layers,
more weight and more size.”1 One solution to creating smaller
batteries is to fabricate 3-dimensional microelectrode arrays
consisting of high aspect ratio carbon posts (carbon posts that
are much taller than they are wide). These posts (between 100
nm to 1 nm in diameter) serve as the electrodes for carbon
MEMS batteries.3
This graphic illustrates an array of carbon posts fabricated using a LIGA micromachining process.
These posts have an aspect ratio of about 10:1. Imagine these posts at a ratio of 100:1.
Electroacoustic, Electromagnetic, and Electrostatic Transducers
Electroacoustic transducers work with sound energy and electrical energy.
Common electroacoustic transducers:
• Loudspeaker – Converts an electrical signal into sound
• Microphone – Converts sound waves in air into
an electrical signal
• Hydrophone - Converts sound waves in water
into an electrical signal.
MEMS hydrophones are currently being used to
detect various sounds within our oceans. Anchored
to the bottom of the ocean or dragged behind a ship,
micro-sized hydrophones detect the sounds
generated by ships, submarines, ocean waves and
marine animals. They also hear tertiary waves
created by earthquakes or any movements within the
earth’s crust.4
Common electromagnetic transducers:
• Magnetic cartridge – Converts motion in a magnetic field into an electrical energy
• Generator – Converts motion in a magnetic field into electrical energy
An electromagnetically driven and sensed MEMS gyroscope is currently on the market. This
gyroscope uses a permanent magnet and a resonating “ring” to detect rotation or motion.5
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Introduction To Transducers
Common electrostatic transducers:
• Electrometer – Converts static or energy from a vibrating reed into electricity
• Van de Graaf generator – Converts static into high voltage (see figure below)
Van de Graaf Generator:
Converts a built up charge
of static electricity into a
high voltage
MEMS electrostatic transducers can be found in and are being researched for use in MEMS
resonators, on/off valves for fuel injection, and drop ejectors that use an electrostatic driven piston.6
A common electrostatic microtransducer is the comb drive. MEMS comb drives are found in both
actuators and sensors. Referring to the SEM image below, you can see that a comb drive consists of
two interlaced “combs”. One comb is stationary and one moves; one comb is at ground potential and
another comb receives a positive voltage. When the voltage is applied, electrons flow from ground to
the tips of the comb teeth on the grounded comb.
There is now a positive and negative charge on
opposite combs, pulling the moveable comb
inward. When the voltage is removed, the
moveable comb is returned to its original position
by springs that are built into the system. Therefore,
as you can see, a comb drive is converting
electrostatic energy into movement or mechanical
energy. This movement can be used to move
something, like a switch or a gear, turning the comb
drive into an actuator.
Scanning Electron Microscope (SEM)
image of a comb drive.
Courtesy of Sandia National Laboratories, SUMMiT(TM)
Technologies, www.mems.sandia.gov'
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Introduction To Transducers
Electromechanical Transducers
Electromechanical transducers are transducers that either convert electrical to mechanical energy or
motion, or convert mechanical movement such as deformation or stress into electrical energy.
Electromechanical Transducers – (Some are also called actuators)
• Strain gauge – Converts the deformation (strain) of an object into a change in electrical resistance
• Galvanometer – Converts the electric current of a coil in a magnetic field into movement
• Generator – Converts mechanical energy (motion) into electrical energy.
• Motor – Converts electrical energy into mechanical energy (graphic below)
• Microaccelerometer – Converts motion or mechanical energy to electrical energy
• Microgyroscope – Converts rotation or tilt (movement) to electrical energy
As with other types of transducers, electromechanical transducers come in all sizes from macro to
micro. Microgenerators have been developed that may someday replace batteries. A Georgia Tech
MEMS Project has developed a 10 millimeters wide generator that spins a micro-sized magnet above
a mesh of coils fabricated on a chip. The micromagnet spins at 100,000 rpm, producing 1.1 watts,
enough power for a cell phone.7
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Introduction To Transducers
Strain gauges are commonly incorporated into MEMS devices such as pressure sensors and microcantilevers. MEMS strain gauges use the piezoelectric properties of metals and other materials to
change the resistance of the materials when the strain gauge is “stretched” due to mechanical
movement.
This graphic illustrates a microcantilever with a strain gauge used to
measure an increase in cantilever mass.
As the analytes or particles being
analyzed attach to the probe coating on
the cantilever, the mass of the cantilever
increases, causing the cantilever to
“bend” and the strain gauge to lengthen.
This changes the resistance of the gauge
and thus the amount of current flowing
through it. This change in current is proportional to the change in cantilever’s mass.
Microaccelerometer
Microaccelerometers are components found in
many MEMS inertial sensors. The accelerometer
component is a transducer that contains an “inertial
mass” (or proof mass) that moves with a change in
acceleration. An accelerometer consists of two
electrodes – a moveable electrode (the inertial
mass) and a fixed electrode. In the class of a in-line
accelerometer seen in these graphics, the two
electrodes have interlaced “sensing fingers”. One
electrode is grounded. The other electrode is
connected to a voltage. When a voltage is applied,
a capacitance is created between the sensing
fingers. When the mass moves due to an external
force (or acceleration), the capacitance changes.
As a transducer, this accelerometer converts
mechanical energy to electrical energy. As a
sensor, additional electronic circuitry is used to
interpret or quantify the changes in capacitance as
proportional changes in acceleration.
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Introduction To Transducers
Other Types of Transducers
Converts Electrical Signals into Light Energy
Photoelectric Transducers (light to electricity or electricity to light):
• Cathode ray tube (CRT) –Converts electrical signals into light energy for a visual output
(graphic above)
• Light bulb –Converts electrical energy into visible light and heat (explained in next section)
• Laser diode – Converts electrical energy into light energy
• Photodiode - Converts light energy into electrical energy
Thermoelectric Transducers (heat to electricity or electricity to heat):
• Thermocouple – Converts heat energy into electrical energy
• Temperature sensitive resistor (Thermister) – a variable resistor affected by temperature changes
(heat energy to electrical energy)
Other types of Transducers:
• Geiger-Müller tube – Converts radioactive energy into electrical energy
• Quartz Crystal – Converts mechanical stress into electricity (electrical energy)
Micro-sized transducers that use temperature, chemical reactions, and mechanical stress to produce
changes in voltage, resistance, resonant frequency, or light are used throughout microsensors. Such
transducers are used in MEMS pressure sensors, temperature sensors, chemical sensor arrays, and
optical modulators.
Let’s take another look at the incandescent light bulb, a macro-sized photoelectric transducer and its
micro-sized equivalent – the light-emitting diode or LED.
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Introduction To Transducers
The Incandescent Light Bulb (a transducer)
Schematic of an incandescent light bulb.
A power source’s positive and negative
terminals are connected to the bulb’s
terminals. An electrical current flows
through the filament. The resistance of
the tungsten filament converts the
electrical energy into heat and light.
Light bulbs convert electrical energy into light and heat. Specifically, an incandescent light bulb
consists of a vacuum chamber (the glass bulb), a filament (typically made of tungsten), and a positive
and a negative terminal (or contain points) (see the figure above). The negative terminal is the part
that screws into the socket to prevent electrical shock. A
voltage source is placed across the positive and negative
terminals causing current to flow through the filament.
Due the electrical resistance of the tungsten filament, the
filament heats up and gives off light (i.e., electrical energy,
to heat energy, to light energy).
Two micro-sized photoelectric transducers that you are
probably familiar with are the solar cell, which converts
light energy to electrical energy and the light-emitting
diode (LED) that converts electrical energy to light. In a
LED, current flowing through the semiconductor die (or
diode), causes an emission of photons or light. Both of
these devices – the solar cell and LED - are currently
being mass produced and are already smaller and more
efficient than their predecessors.
Light-emitting diode with a micro-sized semiconductor die
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Introduction To Transducers
Summary
A transducer is a device that converts one form of energy into another. Transducers are used in all
aspects of life to measure changes in the environment, to enhance everyday applications, and to learn
more about the world around us. An actuator is a device that converts energy into motion.
Therefore, in some cases, an actuator can also be a transducer. When the output of the transducer is
converted to a readable format, the device is called a sensor.
Regardless of the scale, the operation of macro and micro-sized devices remains the same. With all
such devices, as the transducing components shrink, so do the components for the output circuitry.
The diaphragm micropressure sensor in the picture below is only a few micrometers square. The
electronics that communicate with this device are also in the microscale. This allows for a microsized package that can be mounted in the smallest of places. Through nanotechnology, we are able to
fabricate transducers in the nanoscale. These nanotransducers require nano to microscale
components to complete the sensor or actuator.
Example of a Diaphragm MicroPressure Sensor [University of New Mexico, MTTC]
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Introduction To Transducers
Key Terms
Actuator: A specific type of transducer that coverts energy into motion.
Electroacoustic: The interaction between electrical and acoustic phenomena.
Electrochemical: The interconversion of chemical and electric phenomena.
Electromagnetic: Objects made magnetic by an electric current and vice versa.
Electromechanical: Relating to a mechanical device actuated or controlled by electricity.
Electrostatic: Of or related to electric charges at rest or static charges.
Energy: The sources of energy encompass electrical, mechanical, hydraulic, pneumatic, chemical,
thermal, gravity, and radiation energy. There are two types of energy---kinetic and potential. Kinetic
energy is the force caused by the motion of an object, for example a spinning flywheel. Potential
energy is the force stored in an object when it isn’t moving, such as a battery.
Mechanical: Pertaining to or concerned with machinery or tools.
Optical: Referring to the behavior and properties of light and the interaction of light with matter.
Photoelectric: Relates to the electrical effects caused by light.
Sensor: A device that responds to a stimulus, such as heat, light, or pressure, and generates a signal
that can be measured or interpreted.
Transducer: A substance or device that converts input energy of one form into output energy of
another.
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Introduction To Transducers
References
1.
“Tiny Battery May Power Next-Gen Gadgets”. Arthur Tham. News Digest. 24-Feb-2003.
2.
“Carbon-MEMS Architectures for 3D Micro-batteries” PowerPoint Presentation. Marc
Madou. Department of Mechanical and Aerospace Engineering. UCI, October 14, 2003.
3.
“Integration of Carbon Nanotubes and Carbon Nanofibers to C-MEMS” C. Wang. Michigan
Technological University, US. 2005 NSTI Nanotechnology Conference & Trade Show.
http://www.nsti.org/Nanotech2005/showabstract.html?absno=862
4.
“MEMS for Environmental and Bioterrorism Applications”. Southwestern Center for
Microsystem Education and BioLink. 2009.
5.
“An Overview of MEMS Inertial Sensing Technology.” Jonathan Bernstein. CorningIntelliSense Corp. Feb 1, 2003. ModernMedicine.
6.
“Analysis of Electrostatic MEMS Squeeze Film Drop Ejector.” Edward P. Furlani. Eastern
Kodak Research Laboratories. MEMS: From Micro Devices to Wireless Systems. Vol 7,
Special Issue, October 2009, pp. 78-87.
7.
“MEMS Motor Means No More Dead Batteries, Say Researchers.” Mike Martin.
NewsFactor.com. March 10, 2005.
8.
“Parylene-Based Electrochemical-MEMS Transducers”. Gutierrez, Chistian A., Meng, Ellis.
Journal of Microelectromechcanical Systems, Vol 19, No 6, December 2010.
Disclaimer
The information contained herein is considered to be true and accurate; however the Southwest
Center for Microsystems Education (SCME) makes no guarantees concerning the authenticity of any
statement. SCME accepts no liability for the content of this unit, or for the consequences of any
actions taken on the basis of the information provided.
Support for this work was provided by the National Science Foundation's Advanced Technological
Education (ATE) Program through Grants. For more learning modules related to microtechnology,
visit the SCME website (http://scme-nm.org).
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Introduction To Transducers
What are Transducers? Activity
Participant Guide
Description and Estimated Time to Complete
This learning module is one of three SCME modules that discuss the types of components found in
microelectromechanical systems (MEMS). This module covers “transducers” – what they are, how
they work and how they are used in both macro and micro-sized systems. Two related learning
modules cover MEMS sensors and actuators.
This activity provides you the opportunity to further increase your knowledge and understanding of
transducers both in the macro and micro-scales. You will explain how specific transducers work.
Estimated Time to Complete
Allow 2 hours to complete this activity.
Introduction
A transducer is any device that converts one form of energy into another. For example, a
microphone converts sound into electrical impulses and a loudspeaker converts electrical impulses
into sound (i.e., sound energy to electrical energy and vice versa). A solar cell converts light energy
into electricity (electrical energy) and a thermocouple converts heat energy into electrical energy.
A sensor is a device that receives and responds to a signal. This signal must be produced by some
type of energy such as heat, light, electrical, motion, or chemical reaction. In many cases, the
energy input to a sensor is the output of a transducer.
Transducers and sensors usually work hand-in-hand. Many sensors consist of a transducer and the
electronics needed to evaluate the transducer’s input and output. Therefore, a sensor can be defined
as a device that receives and responds to a signal. This signal is produced by some type of energy,
such as heat, light, motion, or chemical reaction that, in many cases, is the output from a transducer.
Once a sensor detects one or more of these signals (an input), it converts it into a readable
representation of the input signal.
Activity Objectives and Outcomes
Activity Objectives
• Define transducer.
• Explain how two different types of transducers work.
• Identify the micro equivalent of two macro-sized transducers.
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What are Transducers? – Activity
Activity Outcomes
Upon completion of this activity you should have a more in-depth understanding of transducers, the
different types of transducers, and the differences and similarities between macro and micro-sized
transducers..
Documentation
The documentation for this activity consists of a written report. Details of the report are given in the
following procedure.
Documentation should include the following:
• Information required in the activity procedure
• Graphics (if available)
• References for materials, information, and graphics
• Answers to the Post-Lab Questions
Activity: What are Transducers?
Procedure:
1. Select two transducers that you would like to research further. The transducers you select can
be from the following list or one from the list and another from your personal interests.
a. Thermocouple
b. Gyroscope
c. Light bulb
d. Battery
e. Microphone
f. Motor
2. Research the two transducers and write a report that addresses no less than the following:
a. Type of transducer
i. What type of transducer is this (electrochemical, thermoelectric, etc.)?
ii. Is this transducer macro-sized, micro-sized or both?
b. Operation
i. How does this transducer work at the macro-scale?
ii. How does this transducer work at the micro-scale?
iii. If this is a macro-sized only transducer, what is a micro-sized transducer that works
similar or is used in similar applications?
iv. What are the similarities and differences between the macro and micro-scaled
transducers?
c. Applications
i. What are some current applications for this transducer in both the macro and microscales?
ii. What are some possible applications for which this transducer could be used?
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What are Transducers? – Activity
Post-Lab Questions
1. What is a transducer?
2. How does a transducer differ from a sensor?
3. How does a transducer differ from an actuator?
4. Identify at least five types of transducers or sensors found in your home and explain what is
transduced.
Support for this work was provided by the National Science Foundation's Advanced Technological
Education (ATE) Program through Grants. For more learning modules related to microtechnology,
visit the SCME website (http://scme-nm.org).
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What are Transducers? – Activity
Introduction to Transducers
Final Assessment
Participant Guide
Introduction
The purpose of this assessment is to determine your understanding of transducers now that you have
completed the Introduction to Transducers Learning Module.
1. An incandescent light bulb is a device that converts heat energy into electrical energy. A
incandescent light bulb is a(n)
a. sensor
b. transducer
c. actuator
d. sensor and transducer
e. transducer and actuator
2. Which of the following BEST describes a transducer? A device that
a. quantifies a change between an input and output
b. converts one form of energy to another form of energy
c. senses a change in its input and produces a readable output
d. converts a change on the input into a proportional movement
3. Which of the following devices is both a transducer and an actuator?
a. Solar cell
b. Thermocouple gauge
c. Electric motor
d. Fuel cell
4. Which of the following BEST describes an electrochemical transducer?
a. Converts electrical energy into chemical energy seen either as a change or a reaction.
b. Converts motion or convection within a chemical into electrical energy.
c. Converts electrical energy into motion or convection within a chemical.
d. Converts the energy from a chemical change or reaction to electrical energy.
5. Galvanometers and generators are both what type of transducer?
a. Electrostatic
b. Electromechanical
c. Thermoelectric
d. Electroacoustic
Southwest Center for Microsystems Education (SCME)
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6. Which of the following devices is an electrostatic transducer?
a. Cathode ray tube (CRT)
b. Incandescent light bulb
c. Comb drive
d. Accelerometer
7. A strain gauge is a transducer that converts
a. mechanical stress or motion into electrical energy
b. electrical energy into motion or mechanical stress
c. mechanical stress or motion into heat
d. heat into motion or mechanical stress
8. One solution for long-lasting batteries in the micro-scale is to build a battery that consists of a
a. two-dimensional array of stacked, paper-thin flat electrodes.
b. two-dimensional array of low aspect ratio stacked carbon posts.
c. three-dimensional array of low aspect ratio carbon posts.
d. three-dimensional array of high aspect ratio carbon posts.
Support for this work was provided by the National Science Foundation's Advanced Technological
Education (ATE) Program through Grants. For more learning modules related to microtechnology,
visit the SCME website (http://scme-nm.org).
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Introduction to Transducers Final Assessment
Southwest Center for Microsystems Education (SCME)
Learning Modules available for download @ scme-nm.org
MEMS Introductory Topics
MEMS Fabrication
MEMS History
MEMS: Making Micro Machines DVD and LM
(Kit)
Units of Weights and Measures
A Comparison of Scale: Macro, Micro, and Nano
Introduction to Transducers
Introduction to Sensors
Introduction to Actuators
Problem Solving – A Systematic Approach
Crystallography for Microsystems (Crystallography
Kit)
Deposition Overview Microsystems (Science of Thin
Films Kit)
Photolithography Overview for Microsystems
Etch Overview for Microsystems (Bulk
Micromachining – An Etch Process Kit)
MEMS Micromachining Overview
LIGA Micromachining Simulation Activities (LIGA
Micromachining – Lithography & Electroplating
Kit)
Manufacturing Technology Training Center Pressure
Sensor Process (Three Activity Kits)
A Systematic Approach to Problem Solving
Introduction to Statistical Process Control
Learning Microsystems Through Problem Solving
Activity and related kit
MEMS Applications
MEMS Applications Overview
Microcantilevers (Microcantilever Model Kit)
Atomic Force Microscope Overview
Micro Pressure Sensors and The Wheatstone Bridge
(Modeling A Micro Pressure Sensor Kit)
Micropumps Overview
Nanotechnology
Nanotechnology: The World Beyond Micro
(Supports the film of the same name by Silicon
Run Productions)
BioMEMS
BioMEMS Overview
BioMEMS Applications Overview
DNA Overview
DNA to Protein Overview
Cells – The Building Blocks of Life
Biomolecular Applications for bioMEMS
BioMEMS Therapeutics Overview
BioMEMS Diagnostics Overview
Clinical Laboratory Techniques and MEMS
MEMS for Environmental and Bioterrorism
Applications
Regulations of bioMEMS
DNA Microarrays (DNA Microarray Model Kit
available)
Microtechnology of Pacemakers
RevisedJanuary2017
Safety
Hazardous Materials
Material Safety Data Sheets
Interpreting Chemical Labels / NFPA
Chemical Lab Safety
Personal Protective Equipment (PPE)
Check our website regularly for the most recent
versions of our Learning Modules.
For more information about SCME
and its Learning Modules and kits,
visit our website
scme-nm.org or contact
Dr. Matthias Pleil at
[email protected]
www.scme-nm.org