GB706430A - Asymmetrical cold cathode flip-flop circuit - Google Patents

Abstract

706,430. Electronic counting apparatus. NORTHROP AIRCRAFT, Inc. June 11, 1951 [June 12, 1950], No. 13812/51. Class 106 (1). (Also in Group XL (c)] Fig. 4 shows a binary counter comprising a cascaded connection of trigger circuits of the type shown in Fig. 3 in which negative-going triggering pulses from source 14 are applied via rectifier 13 to the anode 2 of the cold-cathode gas tube 1. Cathode 4 is connected to earth via neon tube 21 and constant voltage source 22 in parallel with isolating resistor 20 and constant voltage source 15. The voltage difference between sources 15 and 22 is made equal to or slightly less than the maintaining voltage of tube 21. If initially there is a discharge between anode 2 and cathode 3 the voltage drop across resistor 10 limits the voltage of source 7 to the maintaining voltage of the tube 1. Capacitor 17 charges to a potential exceeding that of supply 15 so that when a negative pulse is applied to anode 2 the discharge to cathode 3 is interrupted and as the anode voltage rises a discharge path to cathode 4 is initiated and neon 21 fires. A subsequent pulse applied to anode 2 extinguishes the discharge to cathode 4 and re-instates that to cathode 3. The maintaining voltage of neon 21 may be selected to be close to the potential difference between cathode 4 and earth so that the constant voltage source 22 may be dispensed with. In Fig. 4 the positive pulse produced at cathode 4 of the first tube 1 when it is triggered over by a negative pulse at anode 2 is differentiated by capacitor 30 and rectifier 31 and the negative going resulting pulse is applied via rectifier 13a to trigger the second stage S. Specification 706,423, [Group XL(c), is referred to.