The courses applied physics and electrical engineering have always been closely linked. As some of you may know, the study association Arago started as a committee of your association, Scintilla. In this article, we will tell you about one of our courses, ‘Instrumentatie’. This course makes us feel most like electrical engineers, so you might also find it interesting. This course is split into four parts: basic concepts, transistor circuits, the operational amplifier and sampling of periodic signals: basic concepts. These four parts all build to a common goal: building a setup of a blinking LED and a photodiode. The goal is to place the LED and the photodiode as far apart as possible so that the photodiode still detects the LED.