CALCULATIONS OF RELAXATION OSCILLATIONS IN GAS TUBE CIRCUITS
HARRY DIAMOND LABS ADELPHI MD
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Temporal voltage-current dynamic characteristics were computed using the Townsend continuity equations and Poissons equation, with suitable initial and boundary conditions. In the current region of the negative static characteristic, small current perturbations initially grow exponentially in time if the external-circuit time constant is greater than the tube current-growth time constant. In a limited range of applied voltages, these oscillations become precisely repetitive in time, corresponding to the well known relaxation oscillations. The frequencies of the oscillations obtained from these calcula tions agree with those measured at HDL more closely than do those obtained from the tradi tional published formula. The inductances and the negative resistances calculated from small amplitude decaying oscillations agree precisely with those calculated using a sinusoidal incre mental applied voltage of the same frequency and average current. Qualitative agreement is also obtained with laboratory measurements of those quantities. Relaxation oscillations are also calculated using voltages that closely approximate the peaks of 60-cps applied voltages. Most of the calculations presented are for an argon gap of 1 gm and for a pressure of 2 torr. Experimental data are presented for both argon and hydrogen.