US2831127A - Trigger control-circuit arrangement - Google Patents

Description

April 15, 1958 J. W. BRAICKS TRIGGER CONTROL-CIRCUIT ARRANGEMENT Filed April 5. 1955 INVENTOR JOHAN WIM BRAICKS AGEl b United States Patent 9 TRIGGER CONTROL-CIRCUIT ARRANGEMENT Johan Wim Braicks, Eindhoven, Netherlands, assignor, by

mesne assignments, to North American Philips Company, Inc., New York, N. Y., a corporation of Delaware Application April 5, 1955, Serial No. 499,413

Claims priority, application Netherlands May 7, 1954 3 Claims. (Cl. 307-885) The invention relates to a control-circuit arrangement for an electric trigger. It has for its object to provide an arrangement by means of which control-pulses supplied to this arrangement cause the trigger to change over from one position to the other and produce at the same time pulses corresponding to the position of the trigger.

In accordance with the present invention, two controlpoints of the trigger are coupled with the respective base electrodes of two transistors having emitter-collector paths included in parallel branches. Control-pulses are fed to the two emitter electrodes of these transistors, these pulses controlling the said trigger via the emitterbase capacity of the transistors and producing, across output resistors of these transistors, pulses which correspond to the position of the trigger.

The invention will be described more fully witlrreference to the accompanying drawing, wherein:

Fig. l is a schematic diagram of an embodiment of the trigger control-circuit arrangement of the present invention; and

Fig. 2 is a graphical presentation of the base current versus time curve of the control-circuit arrangement of Fig. 1.

Referring to Fig. 1, reference numeral 1 designates a trigger of known type, comprising two transistors 2 and 3, the collector electrode of each of which is coupled with the .base electrode of the other transistor through suitably chosen impedances 4, 5 and 6, 7, so that at two control-points 8 and 9 of the trigger are produced voltages, which correspond to the position of the trigger, i. e. the position in which the transistor 2 is conductive and the transistor 3 is cut ofi, or conversely. If a pulse is applied to one of these control-points, the trigger changes over into the other position, after which, at the occurrence of a new control-pulse (bistable trigger) or if desired, after a predetermined time, spontaneously (monostable trigger) the trigger returns to its initial position.

After having been converted in an auxiliary transistor 12 into current pulses of adequate energy, the controlpulses 11 are supplied to the control-points 8 and 9 through the emitter-base electrode paths of two transistors 13 and 14, of which the emitter-collector paths are included in two parallel branches, which include the output resistors 15 and 16 respectively. If the transistor 2 is conductive and the transistor 3 is cut off, the voltages corresponding to this position at the points 8 and 9 have the effect that at the occurrence of the control-pulse 11 the transistor 14 allows this control-impulse to pass to the output resistor 16, across which, consequently, is produced an amplified pulse corresponding to the position of the trigger, while the transistor 3 remains cutoff.

The base current pulse of the transistor 14 then fiowing sutfices at comparatively small control-pulses to cause the trigger 1 to change over to its other position. This base current pulse i as is shown in Fig. 2, as a function of time t, is found to increase first to a considerably higher value m than the values it attains during the latter part of the control-pulse. This property is to be at- 2,831,127 Patented Apr. 15, 1958 tributed to transit time effects of the charge carriers in the transistors 13 and 14, due to which apparently a considerable capacity is operative between the emitter electrodes and the base electrodes of these transistors. While, consequently the current value It would be insufiicient to control the trigger with adequate reliability, the considerably higher current value In is certainly suflicient to this end.

If the transistor 3 is conductive and the transistor 2 is cut ofi, the transistor 13 will, of course allow current to pass to the output resistor 15, across which is then produced an amplified pulse voltage, while the corresponding base current of the transistor 13 causes the trigger to change over to its other position.

The trigger 1 may, of course, be of any different type, for example the type in which the transistors 2 and 3 are driven invariably in the forward direction, whereas in the stable or metastable positions of the trigger the collectorbase current amplification factor of one of these transistors drops below 1, or of the type in which use is made of only one point-contact transistor. Instead of using pup-transistors, as shown, use may be made of transistors of the npn-type.

If, more particularly, the transistor 12 is replaced by a transistor of the npn-type, the emitter electrode and the collector electrode being then interchanged, the arrangement may be driven by positive control-pulses 11. Thus also positive output pulses would be produced across the resistors 15 and 16, Which facilitate a cascade connection of the control-circuits. To this end, if desired, the transistors 12, 13 and 14 may be of the npn-type and the supply source of the entire circuit arrangement l2, 13, 14, 15, 16 would be changed in polarity.

What is claimed is:

l. A circuit arrangement for controlling an electric trigger circuit having two control points, comprising a pair of transistors having emitter, collector and base electrodes, emitter-collector paths and apparent emitter-base capacities, means for coupling each of said control points to a respective base electrode of said transistors, means for connecting said emitter-collector paths in parallel, an output resistor connected in each of said emitter-collector paths, means for applying control pulses in common to the emitter electrodes of said transistors thereby to control the operating position of said trigger circuit through said apparent emitter-base capacities, and means for deriving output pulses corresponding to the operating position of said trigger circuit from said output resistors.

2. A circuit arrangement as claimed in claim 1, wherein said means for applying control pulses in common to the emitter electrodes of said transistors comprises a third transistor having an input electrode and an output electrode, means for applying control pulses to said input electrode and means for connecting said output electrode in common to the emitter electrodes of said transistors.

3. A circuit arrangement for controlling an electric trigger circuit having two control points, comprising a pair of transistors having emitter, collector and base electrodes and apparent emitter-base capacities, means for coupling each of said control points to a respective base electrode of said transistors, a source of supply voltage having two terminals, an output resistor connected between the collector elcctrode of each of said transistors and one of the terminals of said source in parallel circuit arrangement, means for interconnecting the emitter electrodes of said transistors, a third transistor having emitter, collector and base electrodes, means for connecting the collector electrode of said third transistor to said interconnecting means, means for coupling the emitter and base electrodes of said third transistor to the other termi- 11211 of said source, means for applying control pulses to J the base electrode of said third transistor thereby to control the operating position or said trigger circuit through said apparent emitter-base capacities, and means for de riving output pulses corresponding to the operating position of said trigger circuit from said) output resistors.

References Cited in the file of this patent

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