| 摘要 |
PURPOSE:To suppress noise due to a motor fan, by controlling the rotational frequency of the motor fan according to detected data from an outside-air temperature sensor. CONSTITUTION:The input of the analog data 2 of temperature detecting signal from an outside-air temperature sensor 1, to a rotational frequency regulating circuit 5 via an A/D converter circuit 3 is provided. By the rotational frequency regulating circuit 5, AC voltage fed to the motor section of a motor fan 6 according to the digital data 4 of a temperature data is regulated. As a result, noise can be lowered to a fixed level. |
