Especially in neuroscience, the physiology of ion channels has always been a major topic of interest. The development of the patch-clamp technique in the late 1970s has given electrophysiologists new prospects. It allows high-resolution current recordings not only of whole cells, but also of excised cellular patches. Even single-channel opening events can be investigated. However, with its complex technical, physical and biological background, the need for highly sensitive equipment and the huge amount of skills required of the experimenter, electrophysiology is still one of the most challenging methods in daily laboratory work.