| 摘要 |
PURPOSE:To control the rotation speed of a fan according to connecting and disconnecting of an option part, by providing an interface capable of detecting the fact that the option part is connected to a power supply connector of the option part where the temperature rise is strictly limited. CONSTITUTION:The rotation speed of a fan 7 is variable corresponding to voltage. And, one of the terminals of the fan 7 is connected to a DC voltage VA, and the other to a ground via a resistor 8, and to a power supply connector 6' of an option part 5 via a resistor 9 including a resistance value 0OMEGA. A ground terminal is provided on the power supply connector 6' of the option part 5, such as a hard disc, etc. having a large power consumption, where the temperature rise is strictly limited. Therefore, when the option part 5 is not connected, a voltage divided by the resistor 8 is applied to the fan 7, causing the rotation speed of the fan 7 to be lowered. On the other hand, when the option part 5 is connected, a voltage divided by the resistors 8 and 9 in parallel is applied to the fan 7, allowing the fan 7 to rotate at a rotation speed required for cooling the option part 5. |
