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An oscilloscope or oscillograph ( Latin oscillare "to rock", Greek graphein "to write") was used to display the time course of electrical voltages. An oscilloscope is always also an oscilloscope . From the point of view of the device one speaks of an oscilloscope, but from the point of view of the observer it is called an oscilloscope, hence the different designation.

Since the end of the 20th century, oscilloscopes in electrical measurement technology have been largely replaced by digital oscilloscopes which, in addition to various recording functions, also have signal evaluation and storage functions. In common parlance, the terms oscilloscope and oscilloscope are sometimes used synonymously .

A typical undulator tape (about 12 mm wide and many meters long), as during the Second World War in the British Funkabfangstationen was used to encrypted German teletype service record

Especially in the English-speaking world , there was also the term undulator (from English to undulate for "to move in waves ") as a name for an oscilloscope or measuring recorder in which the signal to be recorded was written on a long strip of paper, called undulator tape .


Loop oscilloscope from Max Kohl in Chemnitz, 1905. Contains: synchronous motor, arc lamp, electromagnet with 12 kHz measuring loop, observation device, photographic drum, device for offset multiple exposure.

The term oscilloscope is presumably derived from mechanical methods of recording with a measuring recorder, which were used particularly earlier . These are still used today. For example, a pin was attached to the pointer of a powerful measuring mechanism (e.g. a moving-coil measuring mechanism ). A writing medium is passed under the pen at a constant, but often adjustable, speed. The current pointer position is recorded on the medium, the user receives a plot or record in which the course of the measured variable is recorded over time. The pointer can also be driven by an electric motor. The motor is then controlled with a potentiometric position transmitter and a comparator .


In museums there are also recorders for temperature and humidity. Early flight recorders also worked this way, recording altitude and speed. The paper is usually transported with gear motors or clockworks.

Loop oscilloscope

At the beginning of the 20th century, so-called loop oscilloscopes based on the principle of a galvanometer were used for recording or directly viewing fast signals (approx. Up to 3 kHz) , the light indicators of which were temporally deflected by rotating prism mirrors and directed onto a screen or a sheet of film .

Individual evidence

  1. Undulator ( Memento from January 25, 2017 in the Internet Archive ) Brief explanation (English) and sketch. Retrieved January 25, 2017.
  2. Austrian Radio Amateur, Vol. IV, Volume 5, 1927 page 365