PACS:84.30.Ng, 05.45.Xt, 84.40.Ua (all) DOI:10.1070/PU1964v006n06ABEH003620 URL: https://ufn.ru/en/articles/1964/6/j/ Citation: Kaptsov L N "Four lecture demonstrations for courses on the theory of oscillations and radio engineering" Sov. Phys. Usp.6 933–938 (1964)