基本信息
摘要：1358354 Automatic fault indication VEREINIGTE FLUGTECHNISCHE WERKEFOKKER GmbH 30 May 1972 [29 May 1971] 25318/72 Heading H2K [Also in Divisions F4 and H1] In fault-detecting equipment having pilot lamps which light up and/or flash when a fault occurs, each pilot lamp includes a light-emitting semi-conductor diode arranged behind a light diffusing screen. A switch 10 has a printedcircuit board 14 with three gallium arsenide diodes, a coloured filter 16 and a diffusing plate 17. Alternatively a single diode may be mounted on a printed circuit 141. A fault detecting circuit uses luminous constructions 23 which comprise three lightemitting diodes 15 forming a pilot lamp 20, a transistor 22 whose base is connected to a fixed potentiometer formed by Zener diode 26 and a resistance 27 and resistances 24, 25 which control the intensity of light from the diodes by coupled switches 75, 76. When a fault occurs, relay 28, preferably a reed switch, switches the diodes 15 on in pilot lamp 20 and the fault signal is also fed through resistance 60 and diode 61 to a switching stage 50 and a delay unit 40. After a delay, relay 35 is closed and the multivibrator 30 activated thus flashing the main warning lamp 21. The main warning lamp 21 does not flash if the fault lasts only a short time. When the signal of the main warning lamp 21 has been recognized it may be switched off by closing switch 70 or 71. This activates the thyristor 63 thus blocking the fault signal coming through resistance 60. (For Figures see next page.)
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