Elektronischer Zeitmesser

摘要

1,146,494. Transistor oscillator circuits. S. KAKUBARI. 25 May, 1966 [25 May, 1965; 26 June, 1965], No. 23378/66. Heading H3T. [Also in Division G3] A free-running multivibrator circuit for maintaining the oscillations of the balance wheel of an electronic time piece (see Division G3) comprises R.C. coupled transistors V 1 , V 2 . The circuit supplies pulses to a fixed coil 21 mounted between permanent magnets (15, 16) attached to the balance wheel. These pulses magnetize the upper and lower surfaces of the coil which therefore deflects the balance wheel. The movement of the magnets induces pulses in the coil which trigger the transistor V 2 to synchronize the oscillations of the balance wheel and multivibrator. The values T 1 (equal to R 1 ,C 1 ) and T 2 (equal to R 2 C 2 ) are selected so that T 1 <1, R 2 1 or R 1 , R 2 in circuit, R 1 1 being greater than R 1 to provide the necessary initial increase in the pulse width. The pulse width in the steady state operation of the balance wheel is narrower and this narrowing may be achieved automatically by modifications of the circuit to include diodes. The time constant of the multivibrator is initially large since it includes the internal resistance of the diodes but as the amplitude of the triggering pulse from the coil 21 increases, the internal resistance of the diodes decreases, thereby reducing the time constant and the pulse width. Modifications are described of the circuit for automatically reducing the pulse width whilst a further multivibrator circuit, Fig. 12, incorporating a third transistor of NPN type is also described. Reference has been directed by the Comptroller to Specifications 921,948 and 926,419.