In May 1930 Yevgeny Konstantinovich graduated from the university after three years and eight months of studies and got a specialization of physicist, rare for that time. Zavoisky put in an application for post-graduate studies. The Director of the KSU Physics Institute professor V.A.Ulyanin gave him the reference:
"I am glad to support this applicant as I think he can be a good researcher. During his third and fourth years of studying in addition to general practical classes he had done a number of special works in Physics Institute such as capacitance determination and determination of spectra of gases and metals, determination of refractive index of electromagnetic waves in liquid dielectrics and determination of charge-to-mass ratio, investigation of air passage through the contact surface of liquid, - and on the whole comrade Zavoisky showed interest and disposition for experimental physics".
Post-graduate studies lasted 2-2,5 years. According to the program of specializations for post-graduate students, dated February 1932, Zavoisky must get a considerable teaching training that is why he spent a great deal of time in lecturing. He was charged to give lecture course of "Radio engineering" for students-physicists of the second year. Perhaps, it was the first regular lecture course on Radio Engineering at Kazan University.
Yevgeny Konstantinovich continued to study Kosonogov phenomenon, making experiments on different factors' effect on the mode of ultrashort-wave oscillator, which was built in accordance with the scheme of Barkhausen-Kurtz (retarding) field. Among such factors one can mention length and thickness of wires of the anode external circuit and grid, hand or body approach to anode or grid, anode voltage, filament current, etc.