Albuquerque, New Mexico
June 24, 2001
June 24, 2001
June 27, 2001
6.42.1 - 6.42.60
A Laboratory Experiment in Linear Series Voltage Regulators
Jeffrey S. Franzone University of Memphis
Many advanced electronics courses cover linear voltage regulators from the “black-box” (or IC) perspective. Although this perspective is valid and useful, it doesn’t give students much opportunity in a laboratory setting to deeply investigate the behavior of the major parts of the regulator, its characteristics, and the reinforcement of transistor theory. Many “canned” linear voltage regulator labs favor the “quick-and-dirty” approach. Students construct a power supply using a linear voltage regulator IC, make a few measurements, and observe empirically the stability of the output voltage with line and load changes. With these labs, students miss the opportunity to see what makes a regulator “tick” and how different elements of the regulator affect particular regulator characteristics. The laboratory experiment presented here tries to address some of the issues that are not covered in depth in common linear voltage regulator experiments. They include:
• Students build a real regulator circuit from discrete transistors. Students actually see the major parts of the regulator and the interaction between each section.
• Students learn the real meaning of terms such as line and load regulation, % efficiency, and maximum and minimum differential voltage by observing what factors in the regulator actually influence these parameters.
• In traditional experiments, constant-current limiting is the only protection scheme shown. This lab not only demonstrates this technique but also foldback-current limiting. The advantage of foldback-current limiting over constant-current limiting is illustrated by an empirical heatsink test. The regulator circuit is first designed with constant-current limiting. The regulator is shorted and students observe that a heatsink is required. Next, the same circuit is constructed with foldback-current limiting. The output is shorted and students observe that a heatsink is not required.
• Students get to simulate on PSPICE the regulator circuit with constant-current limiting and with foldback-current limiting. The waveforms generated from each circuit clearly emphasize the circuit action and effectiveness of each protection scheme and support the laboratory results.
Proceedings of the 2001 American Society for Engineering Education Annual Conference & Exposition Copyright 2001, American Society for Engineering Education
Franzone, J. (2001, June), A Laboratory Experiment In Linear Series Voltage Regulators Paper presented at 2001 Annual Conference, Albuquerque, New Mexico. https://peer.asee.org/9495
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