GB191507997A - Improvements in or relating to Neon Tubes. - Google Patents

Abstract

7997. Claude. G. July 11, 1914, [Convention date]. Void. [Published under Section 91 of the Act.] Vacuum tubes.-A tube for use as a lightning- arrester, a detector for wireless telegraphy, or an indicator for motor ignition circuits contains neon at a pressure of more than 15 mm. of mercury, and electrodes B at a small distance apart, say 2 mm. Such a tube can carry large currents without alteration of its characteristics, and its terminal pressure only increases to a negligible extent with increase of current. With copper electrodes in the form of pointed cylinders, 5 mm. in diameter and 2 mm. apart, and with a gas pressure of 50 mm. mercury, the tube will start at 200-250 volts alternating. By providing the tube with a conducting-coating, for instance, of tin-foil or silver-plating, and charging at 100 mm. mercury, the starting- pressure can be reduced to 150-200 volts. This arrangement is particularly suitable for use as a lightning-arrester. For detecting electric oscillations, an uncoated tube is placed in the circuit of the aÙrial in series with a source of electric pressure nearly sufficient to start it.