A few years ago I was teaching a class on DSOs to a group of technicians. The class was going great and we were well into the second night when one of the students asked a simple question. We had been talking about fuel injector waveforms and how to interpret them when he asked “Where do you hook up the scope?” It then occurred to me that I had overlooked one of the simplest procedures and by doing so had confused at least one of the students.