Laboratory Exercises for Analog Circuits
and Electronics as Hardware Homeworkwith Student Laptop Computer
Instrumentation
Marion O. Hagler
Department of Electrical and Computer
Engineering
Mississippi State, MS 39762 USA
hagler@ece.msstate.edu

Introduction
Since 1999, all ECE undergraduate
students at MSU have laptop computers
 In spring 2005, first course in electronic
circuits will require hardware homeworkStudents construct circuits at home
 Measure circuit performance with audio
capability of laptops as oscilloscope,
spectral analyzer, and signal generator
Basic Approach
By pair wise comparison ofAnalysis
 Measurement
 Simulation


students
Deploy complex, intensely interactive,
learning environments
 Learn to self-assess their workCircuits with inductors andcapacitorsStudent laptop functions as:
Signal generator
 Oscilloscope Spectrum analyzer
Software (~US$90):
Realtime Analyzer (DSSF3 Light version) http://www.ymec.com/products/dssf3e/Circuits with inductors andcapacitorsSimple example: RC low pass filter

RC low pass filter:
white noise spectral response

R = 4700Ω, C = 0.1µF, fc ≈ 340 HzRC low pass filter:
500 Hz square wave response

R = 4700Ω, C = 0.1µF, fc ≈ 340 HzRC low pass filter: squarewave and white noise inputs
1000 Hz square wavewhite noiseRC low pass filter:
impulse response

R = 4700Ω, C = 0.1µF, RC = 0.47 msec

Non-inverting op amp
configurationOp amp GBW ≈ 1 MHz

Non-inverting op amp
configuration
Analysis:Gain without feedback: A = ALF
With feedback:Feedback conserves GBW

1+ j

G = GLF

In both cases: GBW = ALF f BW1ff BW

11+ jf
ALFf BW
GLF

Non-inverting op amp
configuration
Response when G = 96

Measured input:

Measured output:

Simulation:Non-inverting op amp
configuration
Response when G = 342

Measured input:

Measured output:

Simulation:Non-inverting op amp
configuration
Response when G = 535

Measured input:

Measured output:

Simulation:Non-inverting op amp
configuration
Spectral response:

G = measured (analytical)
G = 112 (102)G = 399 (353)
BW = 7 kHz
BW = 2.2 kHz
GBW = 786kHz
GBW = 877 kHz

G = 563 (551)
BW = 1.6 kHz
GBW = 901 kHz

Wien bridge op amp oscillator:
f = 1592 Hz


R = 1000Ω, C = 0.1µF, f = 1592 Hz

Wienbridge op amp oscillator:
f = 1592 Hz
G = 1.025
Waveform:

Spectrum:

G = 1.030

Wienbridge op amp oscillator:
f = 1592 Hz
G = 1.025
Measured spectrum

Simulated spectrum

Simulated spectrum(unequal battery volts;(equal battery volts;(unequal battery volts;

even harmonics)

no even harmonics)

even harmonics)

Op amp inverting integrator


R = 10,000Ω, C = 10nF

Op amp inverting integrator


Input signal

Output signal(2000 Hz square wave)(2000 Hz triangular wave)

Resistive circuitsStudents purchase and use aninexpensive (<US$25) digital
multimeter for measurements

Two loop, 5 resistor circuit
Resistors: 1k, 2.2k, 4.7k, 10k, 15k
 Batteries: 9V, 9VTwo loop five resistor circuit
Write mesh and node equations andsolve with MATLAB Simulate circuit with OrCAD PSpice Measure circuit voltages and currents
with digital multimeter Interactive learning: comparison ofmeasurements and calculations
Two loop five resistor circuit

Plot of the power dissipated in the load
resistor vs. its resistance:

R-2R digital-to-analog
converter
R = 5000ΩBJT RS latch


R = 10kΩDiscussion and Conclusion
Approximate parts list

Students already have bought shaded
parts and used them for hardware
homework in a first year course.

Part description

RadioShackpartnumberPrice $US

15-Range Digital Multimeter, withbattery

22-81023.48

1/4 Watt Resistor Assortment

271-308

6.29

9V Rectangular Battery (2)23-875

6.58

9V Battery Snap Connectors

270-324

2.59

Adjustable resistor, 10k Ohms

271-2821.29

0.01µF Capacitor (2)272-1051

2.380.1µF Capacitor (2)272-1053

2.38741 Operational Amplifier IC

276-007

0.99

General Purpose IC PC Board (5)276-150

8.95

8-Pin IC sockets (2 packages)

276-1995

1.38

Shielded Cables, 1/8" phone plug
to alligator clips (2)42-2421

6.58

Long-Nose Mini Pliers

64-2953

4.99

Soldering Pencil, 15-Watt

64-2051

8.39

0.032” Rosin Core Solder

64-017

1.59

Total

77.86

Discussion and Conclusion
In view of3 years positive results with hardware homework
in a first year course for ECE students,
 Promise of hardware homework to promoteintensely interactive learning environments,
 Success of prototype projects,
ECE faculty voted toDeploy hardware homework in first of restructured
circuit and electronics courses in spring 2005
 Strengthen labs in successive courses in view ofstronger student lab experience in early courses