This resource presents an inquiry-based laboratory module on electrical interference in biomedical measurements for undergraduate engineering courses. The lab focuses on analyzing, characterizing, and mitigating electromagnetic interference (EMI) in low-amplitude biopotential signals.
Students conduct hands-on experiments using oscilloscopes, differential amplifiers, and conductive subjects to investigate interference sources such as 60 Hz power-line coupling, radio-frequency signals, and environmental electromagnetic fields. A key feature is the direct observation of electromagnetic coupling into both the measurement system and the human body, highlighting capacitive pickup and the body’s role in the circuit.
The lab emphasizes identification of common-mode and differential-mode interference, the effects of measurement impedance and loading, modeling using Thevenin equivalents, use of shielding and differential amplification, frequency-domain analysis, and recognition of aliasing.
The module connects experimental observations to real-world requirements, including electromagnetic compatibility (EMC) and safety standards such as IEC 60601-1-2. Students examine how interference affects measurement reliability and system performance.
Unlike traditional step-by-step labs, this module is open-ended and inquiry-based. Students must select measurement settings, configure experiments, and interpret results in conditions where signals may be noisy, distorted, or misleading. The focus is on understanding how measurements depend on instrumentation, configuration, and environment rather than obtaining a single correct result.
A central objective is developing the ability to evaluate data under uncertainty. Students encounter signals that appear valid but may not represent the true physical phenomenon due to interference or sampling effects, requiring critical reasoning and justification.
The module also integrates engineering ethics into technical practice. Students examine how decisions such as ignoring interference, misinterpreting data, or relying on automated settings can lead to incorrect conclusions and unsafe biomedical outcomes. The lab emphasizes intellectual honesty, disciplined analysis, and responsibility under uncertainty.
This work supports ABET outcomes, including application of engineering principles, experimental design, analysis under realistic constraints, recognition of ethical responsibility, and development of engineering judgment.
The module has been implemented in an upper-level biomedical instrumentation course and is designed for adaptability across institutions. It includes a complete instructional package with a structured lab handout, exploratory guidance, ethics prompts, and assessment-aligned data templates.
Overall, the module demonstrates how technical laboratory instruction can simultaneously develop experimental skills, signal analysis capability, and responsible engineering practice.
