Applications of Ohm’s Law #3

I don’t understand this Engineering question and need help to study.

Find an application where Ohm’s Law is used. It can be within a product, as part of the design process, or measuring a physical quantity. Your Ohm’s Law application must be unique. Include any references or sources that you use for the information in your post. Your references must be academically credible, meaning the author must have sufficient qualifications to publish on the subject. At the very least, the author should be a company, organization or individual with the needed qualifications. So that means no Wikipedia, Yahoo Answers, etc. All posts should have references, unless you are posting on a system that you directly have experience with.