In an electrical circuit, it may be useful to have a circuit component with adjustable properties. A potentiometer is just that! Because a potentiometer allows users to manipulate the resistance through a circuit, this passive component has many applications in circuit design. Watch the video below to learn how potentiometers work and how they may be used in biomedical instrumentation applications.
Self-Assessment Questions:
Click here to test your understanding of Potentiometers.
Discussion Questions:
- Potentiometers are useful in a variety of medical and non-medical applications. List two uses for potentiometers in the medical field and a use for potentiometers in non-medical engineering applications. What is the role of the potentiometer in each case?
- One promising biomedical application of potentiometers is in continuous monitoring of sagittal knee motion in a conventional knee brace. Review this study by Büttner et al. on this technology and list its pros and cons. Do you think this technology will be more widely used in brace applications in the future? Why or why not? Incorporate criteria such as cost, ease of use, and accuracy into your answer.
- Potentiometers do not have to scale their resistance linearly, but rather can use logarithmic or digital scaling. How can these different types of resistance scaling be useful for applications with wide resistance ranges or applications that require more fine tuning of resistance?
- Digital potentiometers are most often used when large scale automation of devices is necessary. What are some advantages and disadvantages of this potentiometer type in comparison to manual sliding potentiometers? State design criteria you could use to evaluate this comparison in different stages of the design process. Consult this article by Ševčík on digital potentiometer interfacing and function for help.
- Why would a potentiometer be used as a voltage divider in place of traditional resistors? Can you think of cases where you would want set-value resistors in your circuit instead of a potentiometer for a voltage divider?
Continue Reading:
- C. Büttner, T. L. Milani, and F. Sichting, “Integrating a potentiometer into a knee brace shows high potential for continuous knee motion monitoring,” Sensors (Basel), vol. 21, no. 6, p. 2150, 2021. Read this resource here.
- This study evaluates use of potentiometer technology for sensing of sagittal knee kinematics in healthy subjects’ daily activities and compares the technology’s accuracy to a knee brace standard of care measurement.
- B. Ševčík, “Modeling and signal integrity testing of digital potentiometers,” in Proceedings of the 17th International Conference Mixed Design of Integrated Circuits and Systems – MIXDES 2010, 2010, pp. 570–575. Read this resource here.
- This article discusses the principles of digital potentiometer operation, the equations for resistance change and function, and uses for these circuit elements. The interfacing of digital potentiometers with electronic systems is also discussed.
- S. M. Beckman and T. S. Buchanan, “Ankle inversion injury and hypermobility: effect on hip and ankle muscle electromyography onset latency,” Arch. Phys. Med. Rehabil., vol. 76, no. 12, pp. 1138–1143, 1995. Read this resource here.
- This study looks at the relationship between ankle sprains and reflex time changes by using EMG signals paired with calculated ankle flexion changes. The instrumentation of the ankle perturbation system employs potentiometers and provides an example of potentiometer use in a medical research setting.
About the Creator:
This video was created by a student in the Rice Bioengineering Class of 2023 (used with permission).
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