GB691901A - Improvements in or relating to gas-filled electric discharge tubes and circuit arrangements therefor - Google Patents

Abstract

691,901. Automatic exchange systems. STANDARD TELEPHONES & CABLES, Ltd. June 11, 1948, No. 15815/48. Class 40 (iv). [Also in Groups XIX, XL (a), XL (b) and XL (c)] A counter suitable for use as a dial impulse regenerator comprises a cold cathode discharge tube having a plurality of cathodes arranged opposite a common anode A. The working cathodes 1c, 3c, 5c ... are each connected through a resistance capacity network to ground. Sets of alternate transfer electrodes 2c, 6c ... and 4c, 8c ... are respectively commoned and connected via separate impulsing circuits R41, R43, C31 and R42, R44, C32 to a common biasing point. Any well-known means may be provided for applying negative voltage pulses to C31 and C32. If the gap 1C is initially conducting, the first pulse applied to input 1 transfers the glow via the first transfer gap 2C to the second working gap 3C (see Group XL (c)). The second pulse arrives on input 2 and further transfers the glow to gap 5C and so on. The direction in which the glow moves is determined by the position of the next or first pulse in relation to the conduction gap, e.g. if the first pulse arrives on input 1 when 3C is conducting, the glow moves from right to left and if the first pulse arrives on input 2 it moves from left to right. Thus, a digit may be counted in, and when required counted out in reverse, so avoiding the difficulties of working with complementary numbers. In an alternative arrangement alternate working cathodes are commoned and the number of resistance capacity circuits thus reduced to two. The commoning of the working cathodes and of the transfer electrodes is effected inside the tube envelope. There is only one pulse input which is connected to the working cathode and transfer electrode multiples through rectifier circuits, the arrangement being such that the potential across the working cathode leads neutralizes the effect of the incoming counting pulses on one or other of the transfer electrode multiples in turn. A switch is provided to reverse the connections between the rectifiers and the working cathodes when a reversal in the direction of movement of the glow is required. An initial discharge is established across the first gap in the tube by means of a trigger electrode, which may also be used as a probe to give an electrical indication when the glow returns to the first gap. Specifications 636,668, 639,827, 691,946, [all in Group XL (c)], and 691,947, [Group XL (a)], are referred to.