عنوان مقاله [English]
One of the introductory examples of scientific books and articles on relaxation oscillations is description of a tank containing a liquid and a siphon, which is known as Tantalus Cup. In this article, the author has shown that the origin of the cup can not be found in historical documents, and probably from the late eighteenth and early nineteenth centuries this device has appeared in laboratory and educational centers in Europe as teaching instrument. However, the thirty-second design of Alheyalbook of Banu Musa actually defines the means with the same performance but more completely than Tantalus Cup. In this article, this device is called "hydraulic relaxation oscillator of Banu Musa". First the history of the book and the life of author, Ahmad ibn Musa ibn Shaker Khorasani, is briefly stated. Thereafter, the historical and scientific record of Tantalus Cup is studied and the performance of the Cup is also described. Finally, Banu Musa's hydraulic oscillator based on relaxation is described in detail. The article claims that Banu Musa was the first engineer who used the relaxation oscillator in a mechanical device.