| 摘要 |
925,308. Electric selective signalling systems. BELL PUNCH CO. Ltd. Dec. 10, 1959, No. 42046/59. Class 40 (1). [Also in Groups XIX and XL (c)] An electronic counter comprises a chain of cold-cathode trigger tubes, the anode of each of which is connected to a cathode of a multicathode indicating tube. As described, for a single decade stage, ten cold-cathode trigger tubes 2, 3 . . . 4, 5, are connected by coupling circuits including capacitors 12, 14 . . . 16, 18, the anode of each tube being connected to a cathode 1, 2 . . . 9, 0, of a multi-cathode indicating tube 1. Positive pulses to be counted are applied at a terminal 26, and inverted by a tube 6, the output of which is applied to the anode of the tube 1. The magnitude of the potential difference V 3 -V 0 across the circuit is such that a glow discharge is maintained between the anode and one cathode of the tube 1 and in the associated trigger tube 2-5. Assuming the discharge in the tube 1 is to its " 1" cathode, the drop in potential at the anode 7 of the tube 1 due to the next input pulse cuts off the tubes 1, 2 and when, at the end of the input pulse, the potential rises, the remanent ionized path from the anode 7 of the tube 1 to the " 1 " cathode causes a small current to flow to the cathode "1" which is applied through the condenser 14 to fire the trigger tube 3, causing the discharge in the tube 1 to pass to the " 2 " cathode. To ensure that the first pulse of a series causes the discharge in the tube 1 to be to the " 1 " cathode, a normally open switch 11 is closed and an input pulse with a gradual decay is applied to the terminal 26. A carry pulse is obtained from the resistor 21 in the circuit of the " 0 " cathode of the tube 1 and trigger 5, the provision of a difference diode 22 and R.C. time circuit comprising resistors 23, 25 and a capacitor 24, ensuring that an output pulse is obtained at terminal 27 of the required length to operate a subsequent decade stage (not shown). Specification 925,309 is referred to. |
