AE 305 – Steady-Signal Lab 01 Steady-Signal Instrumentation 2025
new update University of Michigan
AE 305:
Steady-Signal Instrumentation
P.D. Washabaugh, J. Fishstrom, L.P. Bernal, T.B. Smith, Abhishek Kumar and J.K. Edmondson
Purpose
The main objective of this experiment is the introduction to steady voltage and current excitation and
measurement instrumentation. Furthermore, this experiment will provide an introduction to measurement
accuracy and precision, instrument calibration, test matrices, circuit prototyping, circuit linear and non-
linear response characterization, and steady beam deflection phenomenology.
Summary
You will first review some features of a laboratory power supply and a voltmeter. To become familiar
with both of these instruments you will use the voltmeter to calibrate the power supply. An electrical
breadboard with two passive circuits is provided. You will decipher the layout of the circuit and calibrate
the steady voltage responses. An optical sensor that can be employed to measure displacements will be
calibrated by means of a translation stage and a micrometer. This sensor will be used to measure the
deflection of a beam as it is loaded.
Instrumentation
DC power supply; Digital multi-meter; Electrical and opto-mechanical breadboard prototyping kits;
Circuits with linear and non-linear elements; Translation stage, Micrometer, and Reflective Distance
Sensor.
Deadlines Fall 2024:
Pre-Lab Assignment: due at the beginning of your lab section the week of 25 - 29 Aug 25
Post-Lab Assignment: due by 23:59 on 06 Sep 25
Formal Lab Document: no FLD required for this lab
1
, 1 Introduction
Most instruments are characterized in terms of their input and output as a function of time. This input-
output response can be documented by various methods. These include specifications, calibration graphs,
or more mathematically as transfer functions. The simplest subset of this characterization is to remove
time from the system and to consider only the steady response of the instrument. A typical schematic
showing the input and output of a generic device or black box is shown below in Figure 1.
Figure 1: A typical schematic showing the input and output of a generic device.
Here you will perform the first step in this characterization process. You will become familiar with
common instruments that are used to excite and measure a steady response. These include a state-of-the-
art power supply and voltmeter (a subset of a “multimeter”). Along the way you will be exposed to other
laboratory processes and features of experimentation. For instance, you will discover that the voltmeter
in the multimeter is more precise and accurate than the voltmeter that is built into the power supply. They
both can be used to calibrate other instruments. You will discover that measurement accuracy and
precision is not constant, but a function of numerous parameters most notably the excitation and
measurement range. In addition, you will be exposed to actual circuit elements. These include linear
elements such as resistors, capacitors, and non-linear elements such as Zener diodes. These are assembled
into circuits using an electrical breadboard, which is a common component used to facilitate prototyping.
You will also be introduced to a reflective distance sensor that we will use to measure the deflection of
a structure under load without mechanical contact.
Operating procedures, checklists and test matrices are systematically used in engineering practice to
effectively implement safety, and to efficiently conduct experiments and tests. Operating procedures with
suitably designed checklists and test matrices are the keystone of a good experimental program. In this
lab operating procedures and test matrices are used to help you perform the experiments more efficiently.
Even though time has been removed from certain aspects of the experiments, it is always a factor. In all
tests, time is precious. Imagine performing a test on the International Space Station (ISS) where the
Astronaut or Payload Specialist only has 3 hours to spend on your experiment. In order to make maximum
use of time, you would like to get as much accomplished beforehand as possible. A test matrix lists the
tests conditions that should be conducted. Typically, a test matrix is prepared in advance so that hopefully
when it comes time to actually perform the tests, all you have to do is to fill in the blanks. Here several
operating procedures and test matrices are provided as examples. In later labs you will be asked to
produce some of your own.
2
, 1.1 Phenomenology
Though the purpose of this experiment is to introduce steady-signal instrumentation, the application is
steady bending measurement of a beam. The problem you face is that the specific beam material has been
lost to University of Michigan Department of Aerospace Engineering legend, and you must conduct an
experiment to determine a reasonable Young’s modulus and therefore the material.
The simple steady deflection v of a cantilevered beam due to a concentrated load F at position a is given
by
(1)
where x is the position of measurement (i.e., the RDS position) relative to the root, a is the position at
which the load F is applied relative to the root, E is the Young’s modulus of the material, and I is the
cross-section area moment of inertia. See Figure (2).
Figure 2: Steady bending cantilever beam setup. (From [1] Appendix E.)
The material of section 1.1 is from AERO 215 Introduction to Solid Mechanics & Aerospace Structures,
and should be familiar to you; if not, please review the relevant sections of the text Bedford and Liechti.
More generally, AERO dept courses are not closed systems. Be prepared to make use of material from
other courses to supplement the material in AERO 305.
2 Instrumentation
To prepare for this lab you need to know a few things about the equipment that you will be using. Table
1 gives the instrumentation inventory for this experiment, and the following sections offer a short summary
for each item provided. More details are provided by means of appendices or references that contain
selected pages from the manuals. Please note that here you are only required to use only most the basic
features of these instruments.
3
, Table 1: Instrument inventory for Experiment I.
Instrument Manuf. Model Serial # Notes
Power Supply Agilent E3631A TBD 6V and ±25V variable DC supplies
Multimeter Agilent 34405A TBD See manual.
Electrical Breadboard See circuit diagram
2’ x 3’ board; 1/4-20 holes on 1 in.
Opto-Mechanical Breadboard Newport TD-23
grid
1/4-20 holes; micrometer with 1’
Translation Stage Newport 423
max travel stage
6” by 1/100” ruler; 6” by 1/1000”
Distance Measurement Kit
caliper; 1” by 1/10000” micrometer
Reflective Object Sensor Fairchild QRD1113 See manual.
Table 1 is only meant as a guide; the instrument inventory list in your notebook should look similar.
Standard headers include the instrument, manufacturer, model, serial number and some brief notes. The
serial number of an instrument is a unique number that identifies the unit in your bench. You should
include enough information to be able to reproduce the experiment set up as closely as possible, if you
ever have to come back to take more data. The more information you include the better.
Table 1 includes the minimum headers/information required in your AERO 305 notebooks. Note, you must
fill out the instrument inventory table for every experiment with information specific to your bench.
2.1 Power supply
The purpose of a power supply is to provide a constant signal. Many years ago, power supplies were
simple batteries where a chemical reaction produced a very steady voltage provided temperature was
steady and currents were kept small. An almost universal symbol indicating a power supply in a circuit
diagram is shown in Figure 3.
Figure 3: Traditional symbol for a battery, which is also used to represent a power
supply.
Modern power supplies have some advantages and some disadvantages when compared against a battery.
A battery’s best feature is that it has extremely low noise. Power supplies on the other hand have a small
oscillating signal or ripple superimposed on the otherwise constant signal. This residual oscillating signal
is a measure of the quality of the power supply. For instance, the power supply that we use has a 1 mV
ripple. What this means is that the voltage is at best (other errors may still contribute) constant to this
amplitude.
Modern power supplies have other redeeming features over a traditional battery. The signal can be varied
either continuously (for an analog supply) or in small discrete steps (for a digital supply). In addition, the
4
new update University of Michigan
AE 305:
Steady-Signal Instrumentation
P.D. Washabaugh, J. Fishstrom, L.P. Bernal, T.B. Smith, Abhishek Kumar and J.K. Edmondson
Purpose
The main objective of this experiment is the introduction to steady voltage and current excitation and
measurement instrumentation. Furthermore, this experiment will provide an introduction to measurement
accuracy and precision, instrument calibration, test matrices, circuit prototyping, circuit linear and non-
linear response characterization, and steady beam deflection phenomenology.
Summary
You will first review some features of a laboratory power supply and a voltmeter. To become familiar
with both of these instruments you will use the voltmeter to calibrate the power supply. An electrical
breadboard with two passive circuits is provided. You will decipher the layout of the circuit and calibrate
the steady voltage responses. An optical sensor that can be employed to measure displacements will be
calibrated by means of a translation stage and a micrometer. This sensor will be used to measure the
deflection of a beam as it is loaded.
Instrumentation
DC power supply; Digital multi-meter; Electrical and opto-mechanical breadboard prototyping kits;
Circuits with linear and non-linear elements; Translation stage, Micrometer, and Reflective Distance
Sensor.
Deadlines Fall 2024:
Pre-Lab Assignment: due at the beginning of your lab section the week of 25 - 29 Aug 25
Post-Lab Assignment: due by 23:59 on 06 Sep 25
Formal Lab Document: no FLD required for this lab
1
, 1 Introduction
Most instruments are characterized in terms of their input and output as a function of time. This input-
output response can be documented by various methods. These include specifications, calibration graphs,
or more mathematically as transfer functions. The simplest subset of this characterization is to remove
time from the system and to consider only the steady response of the instrument. A typical schematic
showing the input and output of a generic device or black box is shown below in Figure 1.
Figure 1: A typical schematic showing the input and output of a generic device.
Here you will perform the first step in this characterization process. You will become familiar with
common instruments that are used to excite and measure a steady response. These include a state-of-the-
art power supply and voltmeter (a subset of a “multimeter”). Along the way you will be exposed to other
laboratory processes and features of experimentation. For instance, you will discover that the voltmeter
in the multimeter is more precise and accurate than the voltmeter that is built into the power supply. They
both can be used to calibrate other instruments. You will discover that measurement accuracy and
precision is not constant, but a function of numerous parameters most notably the excitation and
measurement range. In addition, you will be exposed to actual circuit elements. These include linear
elements such as resistors, capacitors, and non-linear elements such as Zener diodes. These are assembled
into circuits using an electrical breadboard, which is a common component used to facilitate prototyping.
You will also be introduced to a reflective distance sensor that we will use to measure the deflection of
a structure under load without mechanical contact.
Operating procedures, checklists and test matrices are systematically used in engineering practice to
effectively implement safety, and to efficiently conduct experiments and tests. Operating procedures with
suitably designed checklists and test matrices are the keystone of a good experimental program. In this
lab operating procedures and test matrices are used to help you perform the experiments more efficiently.
Even though time has been removed from certain aspects of the experiments, it is always a factor. In all
tests, time is precious. Imagine performing a test on the International Space Station (ISS) where the
Astronaut or Payload Specialist only has 3 hours to spend on your experiment. In order to make maximum
use of time, you would like to get as much accomplished beforehand as possible. A test matrix lists the
tests conditions that should be conducted. Typically, a test matrix is prepared in advance so that hopefully
when it comes time to actually perform the tests, all you have to do is to fill in the blanks. Here several
operating procedures and test matrices are provided as examples. In later labs you will be asked to
produce some of your own.
2
, 1.1 Phenomenology
Though the purpose of this experiment is to introduce steady-signal instrumentation, the application is
steady bending measurement of a beam. The problem you face is that the specific beam material has been
lost to University of Michigan Department of Aerospace Engineering legend, and you must conduct an
experiment to determine a reasonable Young’s modulus and therefore the material.
The simple steady deflection v of a cantilevered beam due to a concentrated load F at position a is given
by
(1)
where x is the position of measurement (i.e., the RDS position) relative to the root, a is the position at
which the load F is applied relative to the root, E is the Young’s modulus of the material, and I is the
cross-section area moment of inertia. See Figure (2).
Figure 2: Steady bending cantilever beam setup. (From [1] Appendix E.)
The material of section 1.1 is from AERO 215 Introduction to Solid Mechanics & Aerospace Structures,
and should be familiar to you; if not, please review the relevant sections of the text Bedford and Liechti.
More generally, AERO dept courses are not closed systems. Be prepared to make use of material from
other courses to supplement the material in AERO 305.
2 Instrumentation
To prepare for this lab you need to know a few things about the equipment that you will be using. Table
1 gives the instrumentation inventory for this experiment, and the following sections offer a short summary
for each item provided. More details are provided by means of appendices or references that contain
selected pages from the manuals. Please note that here you are only required to use only most the basic
features of these instruments.
3
, Table 1: Instrument inventory for Experiment I.
Instrument Manuf. Model Serial # Notes
Power Supply Agilent E3631A TBD 6V and ±25V variable DC supplies
Multimeter Agilent 34405A TBD See manual.
Electrical Breadboard See circuit diagram
2’ x 3’ board; 1/4-20 holes on 1 in.
Opto-Mechanical Breadboard Newport TD-23
grid
1/4-20 holes; micrometer with 1’
Translation Stage Newport 423
max travel stage
6” by 1/100” ruler; 6” by 1/1000”
Distance Measurement Kit
caliper; 1” by 1/10000” micrometer
Reflective Object Sensor Fairchild QRD1113 See manual.
Table 1 is only meant as a guide; the instrument inventory list in your notebook should look similar.
Standard headers include the instrument, manufacturer, model, serial number and some brief notes. The
serial number of an instrument is a unique number that identifies the unit in your bench. You should
include enough information to be able to reproduce the experiment set up as closely as possible, if you
ever have to come back to take more data. The more information you include the better.
Table 1 includes the minimum headers/information required in your AERO 305 notebooks. Note, you must
fill out the instrument inventory table for every experiment with information specific to your bench.
2.1 Power supply
The purpose of a power supply is to provide a constant signal. Many years ago, power supplies were
simple batteries where a chemical reaction produced a very steady voltage provided temperature was
steady and currents were kept small. An almost universal symbol indicating a power supply in a circuit
diagram is shown in Figure 3.
Figure 3: Traditional symbol for a battery, which is also used to represent a power
supply.
Modern power supplies have some advantages and some disadvantages when compared against a battery.
A battery’s best feature is that it has extremely low noise. Power supplies on the other hand have a small
oscillating signal or ripple superimposed on the otherwise constant signal. This residual oscillating signal
is a measure of the quality of the power supply. For instance, the power supply that we use has a 1 mV
ripple. What this means is that the voltage is at best (other errors may still contribute) constant to this
amplitude.
Modern power supplies have other redeeming features over a traditional battery. The signal can be varied
either continuously (for an analog supply) or in small discrete steps (for a digital supply). In addition, the
4
