| 摘要 |
660,253. Discharge apparatus. STANDARD TELEPHONES & CABLES, Ltd. March 19, 1948 [March 20, 1947], No. 7723/47. Class 39 (i). [Also in Group XL (c)] A cold cathode gas-filled sequence electric discharge tube of the type described in Specification 639,827, and operating in the manner described in Specification 639,839, is employed in a pulse modulation circuit (see Group XL (c)). The tube comprises cathodes in the form of short cylinders, and the preferred gas filling consists of 92 per cent neon, 1 per cent argon and 7 per cent hydrogen at a total pressure of 100 mm. mercury. The discharge gaps may be arranged in a straight line or in a circle, as shown. The anode 113 consists of a circular metal disc and the cathodes 114 are arranged in a circle concentric therewith. An extra cathode 128, so spaced from the anode 113 that a discharge takes place permanently therefrom, is located at the centre of the circle and is connected through an adjustable resistance 129 to an additional voltage source 130 of such a magnitude that the discharge is not extinguished by the extinguishing pulse applied through condenser 126 to the anode 113. This extra cathode provides a means of varying the general ionization level in the tube, as described in Specification 639,827. In a modified circuit, the extra cathode is provided with a corresponding extra anode which is connected separately to the positive H.T. terminal 119. The additional voltage source 130 is then unnecessary, since the extinguishing pulses will not affect the extra anode. |
