Control device for air conditioner

Abstract

Abstract PURPOSE: To eliminate errors in wiring operation and repairing operation, by decreasing the number of lead wires connecting a control unit and a control switch of a control circuit using a two-wire type control switch. CONSTITUTION: In case that a control system of this invention is connected via contacts (b), (c) to a constant-current power source 11 in which current i 1 is passed, the current i 1 is divided to resistances 13 and 15. Here, the current passed to resistance 15 is then passed to a resistance 16 and joins with the current passed through resistance 13. Here, if resistance 17 and transistor 17 are selected such that the terminal voltage of resistance 16 is lower than the base-emitter voltage VBE of transistor 17, a light emitting diode 14 is lighted since the transistor 17 is not energized by the constant current of i 1 . However, if power source 11 for the constant-current circuit is swtiched to another power source 12 by some trouble and a higher current i 2 is passed therethrough, the light emitting diode 14 is short-circuited and turned OFF. By thus switching the constant-current circuit, it is enabled to feed a signal to a control unit. COPYRIGHT: (C)1981,JPO&Japio

Inventors

• 👤 Toshiichi Hayashi

Bibliographic Details