Patent GB-1016402-A (GB)
Title: A transistorised amplifier for maintaining mechanical oscillations or rotary movement
IPC: H03F1/30
Filed: 1963-06-10
Abstract: 1,016,402. Clocks and watches; current regulators. K. DIEHL. June 10,1963 [June 9, 1962; June 29, 1962; Sept. 29, 1962], No. 22981/63. Headings G3T and G3X. [Also in Division H3] The transistor amplifier maintains the oscillations of a timepiece balance in known manner through a magnet on the balance cooperating with a control coil L 1  and a drive coil L 2  in the circuit of a transistor T, powered by a battery B. The amplifier includes a semi-conductor device, in this case a diode D, the resistance of which is dependent on the current in the drive circuit, and which is so connected between a point in the control circuit and a point in the drive circuit that the control voltage at the base of the transistor, and thereby the operating current, remains nearly constant down to a predetermined lower limit voltage of the battery, e.g. whilst the battery falls from 2. 0 to 0. 8 volts. As shown, the semiconductor device is a diode D, having a pronounced bend in its current-voltage curve, connected between the base of the p-n-p transistor T and a tapping 17 of the coil L 2 , so that the diode conducts when the control section conducts. A condenser 21 subdues self-excitation. Further embodiments are disclosed with reference to the following figures (not shown). In Fig. 4, a voltage divider w is provided in the common feed to the emitter, and connection point 17 is on this divider. In Fig. 5, coil L 2  instead of the divider W, is connected into the emitter feed, point 17 being on this coil. In Fig. 9 and 10, the base receives, above a certain operating voltage, a blocking potential increasing with this voltage. One end of L 1  is connected through a point P 0  to the emitter via a condenser C 2  and to the collector via a high resistance R which is adjustable. One end of coil L 2  is connected through a point P 2  to P 0  via a diode D 1 . In Fig. 10 a further condenser C 3  is connected into the feed between L 2  and D 1  whilst a second diode D 2  is connected between P 1  and a point between C 3  and D 1 . In operation, with a new battery, R is adjusted so that sufficient current is produced in L 2  As the voltage falls, the +ve potential on the base is reduced so that the falling battery voltage is compensated. In Fig. 10, in the blocking phase, because of the effect of the magnet on L 2 , point P 1  becomes +ve resulting in current flow via D 2  to the L.H.plate of C 3 . In the subsequent opening phase, P 1  is -ve and P 2  + ve so that C 2  is changed. In Figs. 11 and 12 some of the connections are interchanged. In Figs. 13 to 15, the semi-conductor device comprises a second, regulating, transistor T 2 . In Fig. 13, a condenser C 4  is connected between the base of T 1  and collector of T 2  which is suited to the battery voltage by resistor R. The base of T 2  is connected with a common neutral lead and emitter of T 2  to one end of a coil L 3  linked with L 2 . Between base and emitter of T 2  is a regulating potentiometer P. When L 1  receives an impulse by which the base of T 1  becomes +ve, T 1  conducts and current flows in L 2 . Simultaneously, voltage in L 3  makes emitter of T 2  +ve relative to its base whereby T 2  conducts. The change on T 4  can leak across T 2 , a +ve charge appearing on R.H. plate of C 4  which counteracts the control voltage in L 1 . At high battery voltage, a larger regulating impulse reaches the base of T 1 , this impulse becoming smaller with decreasing battery voltage so that impulses of constant strength are obtained in L 2 . In Fig. 14, L 2  is in the emitter feed of T 1  and C 4  is charged through the base-collector circuit of T 2  whose emitter goes to the C.N.L. and base to a tapping on coil L 2 . During the blocking phase, R.H. plate of C 4  is highly +ve and the other end of L 1  is correspondingly -ve which makes the base of T 2  -ve via the coil part L¢. Consequently the L.H. of C 4  is -ve. In the subsequent operating phase, T 1  base is -ve relative to emitter and T 1  conducts. The upper end of L 2  is -ve. Part of L 2  voltage goes to T 2  base and T 2  conducts, the -ve charge leaving the L.H. of C 4 . Hence a regulating impulse occurs which reduces the control voltage from L 1  on T 1 , the extent of this increasing with the battery voltage. In Fig. 15, the inductance L 1  is made large. Coupled industances L 4 , L 5  are in the base-collector circuit of T 2 . L 1  in the blocking phase changes C 4 . The resulting voltage in the regulating phase at T 1  base is shown in Fig. 16. Coils L 4 , L 5  are so coupled that only by the release impulse transmitted to T 2  base does this transistor carry out a blocking oscillation. This is re-inforced more energetically the higher the battery voltage and no longer occurs when the battery drops below, e.g. 1. 0 V. Figs 17-19 show a clock mechanism in which the coils L 4 , L 5  of Fig. 15 are separated by a shatter 9,12 movable with the balance whereby the blocking oscillations commence when a certain amplitude of the balance is exceeded.