A New Type of Low Frequency Low Voltage Discharge in a Neon Lamp

Abstract

IN recent years a good deal of work has been done on the neon lamp as a means of producing oscillatory discharges of high frequencies. The arrangement for this purpose usually consists in placing a variable condenser in parallel with the two electrodes inside the lamp and connecting this in series with an adjustable resistance to a supply of D.C. voltage. The phenomenon of periodic ‘flashing’ owes its existence to the peculiar characteristics of the neon lamp, namely, to the fact of its having two ‘critical’ voltages. When the voltage across the condenser and the lamp in parallel approaches a value equal to that required to start a flash, a flash is visible. During the flash, the resistance of the gap falls and so does also the P.D. between the electrodes. The flash, however, does not disappear until the P.D. between the electrodes falls below the lower critical voltage. As soon as the flash ceases the condenser again begins to charge up to the upper critical value, and the process is automatically repeated. This explanation was given by Mecke and Lambrez (Phys. Zeit., 27, 86; 1926). Using the above arrangement, periodic discharges of high frequencies have been obtained by a number of workers.