| 摘要 |
<p>1473785 Light responsive switch FABRIQUE D'HORLOGERIE LA VEDETTE SA 31 Jan 1975 [8 Feb 1974] 4253/75 Heading G1A [Also in Division H2J] Such a switch comprises a voltage divider composed of resistor 10 and photo-conductor 11, transistors 13, 14 blocked or conductive according to illumination of photo-conductor 11, switch 20, a bi-stable circuit with transistors 15, 16 controlling via transistor 21, a motor 22 in its collector circuit, step down gearing 25, 26 26a, 27, 27a, 28 with cams 30, 31, 32 on final shaft 29 and contacts 23, 24, which after a delay open or close one or more lighting circuits. The circuit may be supplied at terminals 8, 9, from a 220V 50Hz supply by circuit 3, 5, 6, 4 which has stabilizer Zener diode 7 which delivers 12VDC or from a D.C. supply of 6V, 9V, &c. When photo-conductor 11 is less illuminated its resistance increases until transistor 13 and hence transistors 14 and 15 become conductive and transistor 16 blocks so that the voltage at B increases and the current from transistor 21 drives motor 22 so that cams 31 and 32 close contacts 23 and 24 and then cam 30 moves switch 20 to points 17 and 19 cutting off the motor. When photo-conductor 11 is illuminated so that its resistance drops, transistors 13, 14, 15 are blocked so that the voltage at A rises and motor 22 rotates to interrupt contacts 23, 24 and hollow 34 of cam 30 changes switch 20. Fig. 3 (not shown) shows the apparatus in an opaque casing (35). Photoconductor 11 receives light through aperture (36) with adjustable shutter (37). In Fig. 4 (not shown) the photo-conductor is mounted in an adjustable antenna (40) which is on a fixed support (39) separate from the casing (38). A timing switch may also be incorporated.</p> |
