A Hydraulic Circuits Laboratory – To Improve Student Understanding Of Basic Electricity

Concepts of voltage and current have often seemed foreign to students since they are measurable but not directly visible. For nearly forty years the author has introduced basic circuit concepts using a fluid analogy and has seen similar explanations in various textbooks. This year a true “wet lab” has been implemented to illustrate the concepts of voltage and current as well as Kirchhoff’s current law and the transient behavior of RC circuits. The hydraulic lab takes place as a portion of a supplementary lab for Circuits I which includes hands-on experiments with circuit components, timers, LED’s, and op amps. Student response to the hydraulic circuit lab will be discussed. This project was supported in part by a grant from the Keck Foundation with a purpose of updating laboratories and developing interdisciplinary laboratory experiments. Introduction The circuit concepts of voltage and current have often seemed foreign to students since they are measurable but not directly visible. Many students dread taking a circuits course because they have no “feeling” for voltage, current, resistance, capacitance, or inductance. It might be akin to never having used a prybar, rolled an object on wheels, or used a screwdriver or pulley. Some students have never even siphoned water from one container to another. (The primary author (RWG) admits to having a hard time during his sophomore and junior years trying to understand these basic concepts, they were simply mathematical equations. He had, when younger, thought that there was something magical about working with mathematics. It took a very long time for him to regard electrical problems as physical systems to be modeled by mathematical concepts rather than a set of equations to be manipulated to obtain an answer.) All engineering students at LeTourneau University take the same Circuits I course, whether their specialty is electrical, mechanical, biomedical, materials joining, or computers. Students in the mechanical concentration must learn the basic circuit concepts as well as those in the electrical concentration. Often the students in the mechanical option are more tactile learners and have difficulty grasping electrical concepts. The first author has been trying to give students a bridge to communicate the basic concepts of electricity, and has found that an analogy to fluid flow can be very helpful. For nearly forty years he has introduced basic circuit concepts using a hydraulic analogy and has seen similar explanations in various textbooks. The water analogy has been used as an explanation on the blackboards (and whiteboards) for several years, but the goal has been to have a more tactile method of communication. This year a true “wet lab” has been implemented to illustrate the concepts of voltage and current, as well as Kirchhoff’s current law and the transient behavior of RC circuits. The hydraulic lab experiment takes place as a portion of a supplementary lab for Circuits I which includes hands-on experiments with circuit components, timers, LED’s, and op amps. This P ge 1.51.2 project was supported in part by a grant from the Keck Foundation with a purpose of updating laboratories and developing interdisciplinary laboratory experiments. Keck funds were used to purchase materials and to hire student workers to make the exercise practical.