Terahertz-range backward wave oscillator – carcinotrons and klynotrons are widely used in radioelectronics systems for solving fundamental and applied problems. Instability of the output signal frequency of the said lamps is not worse than 10?4. The frequency of the carcinotron and klynotron output signal as a rule carried out by changing the operating voltage, i.e. with the expenditure of energy in the control circuit.