ECE 291 - Electrical Engineering Laboratory

# INTRODUCTION

It is well recognized that laboratories are an integral and critical component of engineering education.  This manual is your guide to the first electronic laboratory in electrical engineering and computer engineering programs.  This laboratory, designed to fit the curricula of both programs in the sophomore year is followed by a sequence of more advanced and specialized junior and senior year labs.  The goals of this first laboratory are: (1) to teach you principles of electronic measurements, and to familiarize you with essential instrumentation, (2) to teach you professional laboratory practices, elements of data analysis, presentation of results, and reporting.  Doing laboratory experiments will also help you in understanding textbook knowledge learned in other courses by applying it to real circuits and components.  You will soon discover that drawing a circuit on paper or simulating its performance on a computer screen is not the same as building it with wires and physical components and evaluating it by measurements of voltages or currents.  As some students find to their dismay even such an elementary task as measuring the voltage between two points of a circuit does not necessarily give the "right" value, defined by a simple minded application of an appropriate equation.  A nice digital display on the face of a meter may show a value which makes no sense, if the internal resistance of the meter, capacitance of the connecting cables and the impedance of the circuit are not taken into account.  The fact is that the meter and the cable become a part of the circuit and the circuit performance may thus be changed by the very act of the measurement.  The example illustrates that good experimental data can be obtained only by properly designed measurements and knowledge of the capabilities and limitations of instrumentation.  The most important insights which you may gain in this laboratory work will come from comparison of the expected (theoretical or computer simulated) circuits performance with critically evaluated experimental data.

Professional engineering approach requires using proper experimental methods and procedures..  They include not only good measurement techniques but also proper recording of all relevant information, preparing tables and graphs, etc.  Almost as important as obtaining good data is their proper presentation which often determines success in this laboratory course as it does in engineering practice.

This manual  will guide you through ten sets of experiments.  It is not a “cookbook” giving precise recipes for every step to be taken.  There is often more than one way to achieve a given goal and you are expected to think and decide, for example making choices of the resistors or capacitor values, as an engineer would.  Help is provided in the form of hints and suggestions scattered throughout the text.  There are thus elements of your own design in every set of experiments.

The laboratory does not require extensive theoretical knowledge but you must understand what you are doing.  Reviewing basic principles of circuits and components you work with may be necessary to interpret your results.  A good source may be your notes from the prior or current semester courses on circuits or electronics.

### Acknowledgments

The author acknowledges the use of material in Experiments II, V, and VI from prior Laboratory Manuals for EE291 which were authored by Professors: W. Clemens, K. Sohn, J. Strano and W. Troop.  Special thanks go to Professor Joseph Frank for revising this text and many helpful comments and suggestions regarding the experiments.

Contribution of Professor Arthur Glaser to modifications and improvements in September 2007 edition are greatly appreciated.