GB1509395A - Chronometric device - Google Patents

Abstract

1509395 Electronic timepieces BICOSA SOC DE RECHERCHES 18 June 1975 [19 June 1974 11 July 1974] 26036/75 Heading G3T [Also in Division H3] An electronic timepiece comprises an LC transistor oscillator circuit (110 Fig. 2) to provide a timing Reference signal which is applied via a capacitor 124 to a frequency divider 112 having an output at 1HZ to a decoder 113 which is connected to drive an electro-optical display unit 111 (e.g. liquid crystal). In addition the relatively high voltage (e.g. 7 volts peak) produced by inductor 119 is coupled via a diode 122 to the decoder to activate appropriate segments of the display unit 111. The LC resonant circuit includes the inductor 119 and the intrinsic capacitance of the junctions of transistors 115, 118 and of the inductor. A capacitor 120 plays no significant part in determining the oscillation frequency, its capacitance being low compared to the stray capacitances, and serving primarily to isolate the collector of transistor 118 from the base of transistor 115. The inductor may have a ferrite core. In an embodiment Fig. 3 (not shown) the inductor has primary and secondary winding on the same core whereby the collector of a transistor is coupled to the base thereof. The power source may be a mercury battery. A Zener diode (127) and capacitor (128) Fig.3 (not shown) may be used to stabilize the supply voltage. Suitable component values are given.