A tunnel-diode analogue and its application

The investigation of switching and oscillation phenomena in tunnel diodes has a number of problems associated with it, one of which is the practical difficulty of observing the resulting fast waveforms. The analogue described in the paper facilitates the observation of these waveforms by slowing them down by several orders of magnitude. The parameters of the analogue are easily variable, thus enabling the tolerance of circuits to variations in tunnel-diode parameters to be readily ascertained. Further, the large magnitude of the parameters and the small bandwidth permit investigations of stability criteria, non-linear oscillations and switching to be carried out with ease. The linear stability criterion has been verified and demonstrated experimentally by the use of the analogue. A power-series expansion is assumed for the non-linear characteristics of a tunnel diode, and the steadystate oscillation for a simple series-oscillator configuration with a non-negligible series resistance has been analysed by using the perturbation method of Kryloff and Bogoliuoboff. The tendency for non-linear oscillators to oscillate at a frequency above that predicted by the linear theory has been theoretically explained. The well-known oscillation hysteresis in such oscillators has also been discussed, and some of the theoretical results have been verified experimentally.