Description
ECE 203: Electric Circuits and Systems Laboratory is a 1-credit lab course taught at Michigan State University for Electrical and Computer Engineering majors. The catalog description for this course is: Electrical test equipment and measurement fundamentals. Circuit and filter design using integrated circuit amplifiers. The co-requisite for this course is ECE 202.
Lab Manual and e-Notes
The lab lectures consist of e-Notes explaining the ideas and concepts of each lab experiment based on the principles taught in ECE 201 and ECE 202. These lectures are recorded and can be found on the ECE 203 YouTube channel at: https://www.youtube.com/user/ECE203msu
The lab experiments are intended to teach measurement techniques as well as reinforce concepts taught. As you complete each task in lab you will be asked to record, calculate and evaluate your data. You cannot go on to the next step or circuit unless each task is completed as stated in the lab experiment. This method emphasizes accuracy over speed.
Table of Contents
Lab I – Introduction to the Oscilloscope, Function Generator and Digital Multimeter
PURPOSE: The oscilloscope, function generator and digital multimeter are the basic tools in the measurement and testing of circuits. This lab introduces the first time operation of these instruments.
The concepts covered are:
1. the resistor color code;
2. accuracy of components and the digital multimeter.
The laboratory techniques covered are:
1. voltage amplitude and time measurement with an oscilloscope;
2. measurement of resistors;
3. measurement of resistance using a 4-wire probe.
Lab II – Thevenin Resistance
PURPOSE: This lab looks at techniques for measuring a Thevenin resistance. It also introduces the use of a Proto-Board for the quick assembly of a circuit without the need to solder wires.
The concepts covered are:
1. accuracy of the Infiniium;
2. measuring source resistance in linear circuits;
3. poles and throws of switches;
4. battery performance and characterization;
5. microphone characterization.
The laboratory techniques covered are:
1. using the Infiniium’s Toolbar to measure peak-to-peak voltages;
2. re-programming the function generator’s calibration for High Impedance loads;
3. measuring DC voltage with a digital multimeter.
Lab III – Wheatstone Bridge Applications
PURPOSE: The Wheatstone Bridge has a very unique cancellation property. This lab looks at some of the properties of the Wheatstone Bridge and one application in the use of a compensated scope probe.
The concepts covered are:
1. Wheatstone Bridge with resistive and reactive components;
2. the use of a balanced bridge to compensate for the stray capacitance of a measuring cable and the equivalent impedance of the oscilloscope;
3. capacitor coding.
The laboratory techniques covered are:
1. use of an LCR meter to measure resistance and capacitance;
2. measurement of resistance and capacitance with a Wheatstone Bridge;
3. a procedure for compensating an oscilloscope probe.
Lab IV – Inverting and Noninverting Amplifiers
PURPOSE: The operational amplifier is a basic building block used in many electronic circuits.
The concepts covered are:
1. accuracy of components and instruments;
2. the properties of the ideal operational amplifier;
3. inverting and noninverting amplification.
The laboratory techniques covered are:
1. the measurement of true RMS voltage using a digital multimeter;
2. the use of the dual trace feature of an oscilloscope for measuring gain and phase of an amplifier.
Lab V – Microphone Amplifier
PURPOSE: Long wires in electronic circuits cause problems. In power supply connections they can cause oscillations on the wires to our integrated circuits. In microphones they pick up unwanted signals that also get amplified. We will look how to address these problems in this lab.
The concepts covered are:
1. differential amplification;
2. power supply stability;
3. common-mode noise cancellation;
4. power boosting stage for an op-amp.
The laboratory techniques covered are:
1. measuring RMS voltage with the oscilloscope;
2. one shot triggering.
Lab VI – Noise Canceling / Eavesdropping Headphones
PURPOSE: In this lab, you will build a circuit to cancel background noise without increasing the volume of the music. We will investigate which types of background noise we can cancel and we will modify the circuitry to turn the noise canceling headphones into eavesdropping headphones.
The concepts covered are:
1. bandwidth limiting to reduce noise;
2. using low noise op-amps to reduce noise;
3. using ganged pots to vary two gains simultaneously;
4. using a double-pole-double-throw (DPDT) switch to change the noise canceling headphones into eavesdropping headphones;
5. dispelling myths about noise canceling headphones through testing.
Lab VII – Active Band-Pass Filter
PURPOSE: Active filters are used extensively in audio preamplifier circuits and test instruments. Active filters consist of resistors, capacitors and op-amps and can realize filter functions similar to that of circuits using resistors, capacitors and inductors.
The concepts covered are:
1. multiple loop feedback filters;
2. developing a design procedure for component selection;
3. using a Fourier series to model a periodic wave form;
4. the effects of capacitor quality factor on filter response.
The laboratory techniques covered are:
1. using the x-y feature of the scope to display a Lissajous pattern for tuning;
2. measuring the quality factor of a capacitor using an LCR meter.
Lab VIII – Room Equalizer Design
PURPOSE: Furniture, drapes, walls and rugs cause amplitude and phase distortion when playing music in a confined space. Some tones are suppressed and some tones are enhanced by the room acoustics. One way to compensate for this is to amplify or attenuate the frequencies that are affected, respectively. This is done by dividing up the audio band (20 Hz to 20 kHz) into smaller bands which can be amplified, attenuated or just passed. We will do this with three band-pass active filters. By summing the results we can then put the audio band back together with the compensated music and play this through a power amplifier.
In lab, we have one high quality speaker per lab bench so to play a stereo source of sound we need to add the two channels creating a monaural source of sound.
The concepts covered are:
1. designing a stereo-to-monaural converter;
2. determining design constraints and component selection for the band-pass filters of the equalizer;
3. designing a variable summer
