Patent ID: 7755499
Filing Date: 2010-07-13
Classification: G01F,G01P

Abstract:
1. A detecting apparatus for detecting an operation of a fan, the detecting apparatus comprising: a first current module disposed at an airflow path of the fan, and comprising a first transistor, a second transistor, a third transistor, and a first resistor, the base of the first transistor connected to a power source, and to ground through the first resistor, the collector of the first transistor connected to the power source, the emitter of the first transistor connected to the collector of the second transistor and the base of the second transistor, the base of the second transistor connected to the base of the third transistor, the emitters of the second and third transistors connected to ground, the collector of the third transistor acting as an output; a second current module insulated from the airflow, and comprising a fourth transistor, a fifth transistor, a sixth transistor, and a second resistor, the first and second current modules being mirror-images of each other, the base of the fourth transistor connected to the power source, and to ground through the second resistor, the collector of the fourth transistor connected to the power source, the emitter of the fourth transistor connected to the collector of the fifth transistor and the base of the fifth transistor, the base of the fifth transistor connected to the base of the sixth transistor, the emitters of the fifth and sixth transistors connected to ground, the collector of the sixth transistor connected to the output; and an indicating module comprising a seventh transistor, and an indicating element, the base of the seventh transistor connected to the output to receive a comparision of currents coming from the collectors of the third transistor and the sixth transistor, the collector of the seventh transistor connected to the power source, the emitter of the seventh transistor grounded, turning on or off the seventh transistor controlling the indicating element to indicate operation status of the fan.