Device for testing fan

A fan test device connected between a fan and a motherboard, comprising:

• a first diode and a second diode;
• a first connector and a second connector;
• a first switch chip comprising a first pin connected to a signal pin of the first connector;
• a second switch chip comprising a first pin connected to a signal pin of the second connector;
• a control chip, wherein a first input pin of the control chip is connected to a sense pin of the first connector, a first output pin of the control chip is connected to a second pin of the first switch chip, a first alarm pin of the control chip is connected to a third pin of the first switch chip, a first speed pin of the control chip is connected to a fourth pin of the first switch chip, a second input pin of the control chip is connected to a sense pin of the second switch chip, s second output pin of the control chip is connected to a second pin of the second switch chip, a second alarm pin of the control chip is connected to a third pin of the second switch chip, and a second speed pin of the control chip is connected to a fourth pin of the second switch chip;
• a first electronic switch and a second electronic switch, wherein a first terminal of the first electronic switch is connected to a first control pin of the control chip, a second terminal of the first electronic switch is connected to the a first power terminal, a third terminal of the first electronic switch is connected to a power pin of the first connector, the second terminal of the first electronic switch is connected to an anode of the first diode, the third terminal of the first electronic switch is connected to a cathode of the first diode, a first terminal of the second electronic switch is connected to a second control pin of the control chip, a second terminal of the second electronic switch is connected to the first power terminal, a third terminal of the second electronic switch is connected to a power pin of the second connector, the second terminal of the second electronic switch is connected to an anode of the second diode, the third terminal of the second electronic switch is connected to a cathode of the second diode, the third terminal of the first electronic is connected to the second terminal of the first electronic switch when the first terminal of the first electronic switch is at a high level, the third terminal of the second electronic is disconnected from the second terminal of the second electronic switch when the first terminal of the second electronic switch is at a low level, the third terminal of the second electronic is connected to the second terminal of the second electronic switch when the first terminal of the second electronic switch is at a high level;
• wherein when the second pin of the first switch chip receives a first control signal from the control chip, the first pin of the first switch chip is connected to the fourth pin of the first switch chip, when the second pin of the second switch chip receives the first control signal from the control chip, the first pin of the second switch chip is connected to the fourth pin of the second switch chip, when the second pin of the first switch chip receives a second control signal from the control chip, the first pin of the first switch chip is connected to the third pin of the first switch chip, when the second pin of the second switch chip receives the second control signal, the first pin of the second switch chip is connected to the third pin of the first switch chip;
• wherein the control chip receives signals of speed of the fan from one of the first connector or the second connector, and when the control chip determines the speed of the fan is abnormal, the control chip outputs an alarm signal to the motherboard.