ECE 3110 Labs

Project: EMG Sensor with Audiovisual output

ECE 3110 Course Website
Analog Lab Equipment Documentation and Tutorials

The goal of this lab is to build an electromyogram (EMG) sensor with a bar-graph LED output and an audio output that both indicate the strength of a muscle contraction. Students start with a redesign of the instrumentation amplifier built in Intro. to ECE, then they rectify and high-pass filter to get a running average of the signal. They also define discrete levels to be uses to design an LED indicator. Finally, the design of a VCO connected to a driver and speaker is used to create the audio component.

Lab 1 – Current Mirrors and Differential Amplifiers

Objective: This lab covers MOSFET current mirrors and MOSFET transistor differential amplifiers, both basic building blocks for analog integrated circuits.

In this experiment, you will construct and characterize the following circuits:

  1. A basic MOSFET current mirror (section 6.3.1 in the text)
  2. A simple MOSFET differential amplifier (section 7.1 in the text)
  3. A MOSFET differential amplifier with current mirror biasing


Lab 2 – Common Source Amplifier Frequency Response

the spice must flow!

Introduction: This experiment will demonstrate the frequency and time domain response of a single stage common source MOSFET amplifier. The measured data will be compared to SPICE simulations you have already completed. To save a lot of time and possible frustration, read the section you are working on entirely before performing any measurements.


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Lab 3 – Feedback Amplifier Compensation

Lab 3 picture

Introduction: This experiment will demonstrate the effect of negative feedback on amplifier performance, and demonstrate several methods of frequency compensation. The experiment is divided into two parts: the first part involves the construction and characterization of an amplifier whose poles are accurately set by discrete resistors and capacitors, and in the second part we will close a feedback loop around the amplifier and measure its effect on amplifier performance.


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Lab 4 – Digital to Analog Converters

Lab 4 picture

Introduction: In this experiment you will build and characterize two different 4-bit digital to analog converters (DACs). You will be able to observe the effects of component mismatches on the output signal levels, and we will then analyze the effect of these mismatches on the DACs ability to replicate a sinusoidal signal at its output. The first part of the lab involves building the two DACs and measuring their output characteristics. The measurement data will then be analyzed using Matlab in the third part of the lab.


Lab 5 – EMG Detector with Audiovisual Output

Lab 5 picture

Objective: The goal of this lab is to build an EMG sensor with a bar-graph LED output and an audio output that both indicate the strength of a muscle contraction. The lab is outlined such that you will design and test each circuit that will be used to build a complete system. EMG stands for electromyogram, which is the measurement of electrical potentials created by the contraction of muscles. Typical surface EMG signals for large muscles, such as the bicep, are around 1-2 mV in amplitude. EMG signals contain frequencies ranging from 10 Hz or lower up to 1 kHz or higher.


  • For equipment and procedures, see: Lab5.pdf