| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive circuit for variable-speed fan. SOLUTION: This drive circuit is provided with a computing IC, a Hall IC, an external signal input end and a current control circuit. The drive circuit is controlled inside the fan without need for an external independent circuit. The computing IC is connected to the Hall IC. The computing IC controls two sequentially connected transistors, and the transistors are turned on and off. The alternating excitation of two fan coils is made. The fan is turned. The external input end detects an external signal source. The current of the fan coils through the current control circuit is controlled. Thereby, the rotational speed of the fan is controlled.
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