Patent GB-724605-A (GB)
Title: Electrical circuits using two-electrode devices
Inventor: ODELL ALEXANDER DOUGLAS
IPC: H03K3/313
Filed: 1953-05-22
Abstract: 724,605. Semi-conductor pulse circuits STANDARD TELEPHONES & CABLES, Ltd. May 22, 1953, No. 14479/53. Addition to 706,514. Class 40 (6). [Also in Group XIX] An electrical circuit comprises two " positivegap diodes " as claimed in the parent Specification, which are interconnected so that if either assumes its " on or high-current state when the other is in its on " state, said other diode is switched to its off or low-current condition. The " positive gap diode " has a negative resistance portion in its forward voltage-current characteristic, so that over a certain range the device has two stable current values corresponding to a particular voltage. Many different circuits comprising positive gap diodes are described. Fig. 4 shows a bi-stable circuit in which positive gap diodes NG1 and NG2 are connected through rectifiers to a positive source of voltage V, which is adjusted to be just below the turnover voltage of the diodes. If NG2 is assumed to be in the high-current or on " condition, and NG1 is the low current or off " condition, a positive trigger pulse applied through C to the anode of NG will switch this "on," and the resulting positive pulse across cathode load R3 will be applied via condenser C3 to the cathode of diode NG2 so that this is switched " off." The circuit is similarly restored to the first condition by a positive pulse P2 to the anode of NG2. In a similar circuit (Fig. 6), the cathodes are separately coupled to earth by condensers C4 and C5, and the coupling between the diodes is achieved by means of a common anode load R7. Fig. 9 shows a crossgated binary pair, having a single inpu terminal P for trigger pulses. The basic circuit comprising diodes NG1, NG2 is similar to Fig. 6, except that resistor R7 is replaced by inductor L1 in parallel with a rectifier MR3. If NG2 is " off " and NG1 is " on," the cathode of rectifier MR6 is positively biased, and a positive input pulse at P will thus result in point Y going positive, while X remains substantially at earth potential. The resulting positive pulse on the anode of NG2 switches this " on," which results in a negative pulse being passed through MR2 to switch NG1 off. The next input trigger pulse similarly restores the circuit to the original condition. Fig. 10 shows a scale of N counter comprising a series of diodes NG1, NG2 ... Assuming that NG1 is " on " and the other diodes are "off," whereby the cathode of rectifier MR12 is biased positively, a positive pulse applied at P will pass to the anode of NG2 which is switched " on." The resulting negative anode pulse is applied to the anode of NG1 which is switched off. Each input pulse thus results in successive diodes being switched " on," with all other diodes switched " off." The arrangement may be connected as a ring counter. Other circuits described include a binary counter having a bi-stable circuit as in Fig. 4, in each stage, which divides by two (Fig. 12, not shown); a binary counter with a single diode in each stage (Fig. 13, not shown); a pattern movement register in which stored intelligence is progressed along one stage in response to each pulse (Fig. 11, not shown) and a free-running miltivibrator and a monostable flip-flop (Figs. 14 and 15, not shown). Pulse generators are also described (Figs. 16 and 17, not shown) in which current is applied to a delay line which is terminated by a positive gap diode; this results in the diode being switched from a lowto high-current condition for a period determined by the constant of the line; synchronizing or trigger pulses may be provided in these circuits. They may also be used to feed information to a magnetic drum or other storage device (Figs. 11 and 19, not shown), the diodes being also under the control of coincidence gates.