Computer cooling fan detection circuitry

The utility model provides a computer cooling fan detection circuitry when overtension or high temperature, reminds the user in time to maintain. Its scheme is, including thermistor RT1, resistance R1, resistance R2, resistance R3, resistance R4, resistance R5, resistance R6, resistance R7, resistance R8, resistance R9, comparator U1, comparator U2, operational amplifier U3, logical AND gate U4, field effect transistor Q1, emitting diode D1, emitting diode D2, buzzer BUZ1, buzzer BUZ2, NPN type triode Q2 and radiator fan motor M. The utility model discloses simple structure, used components and parts are few, and are with low costs, when the overtension, the smooth and buzzer BUZ2 warning of emitting diode D1 jaundice, but user reduced voltage, when the temperature risees, the rising of comparator U1's non inverting input terminal voltage, emitting diode D2 turns red solely and the warning of buzzer BUZ1, logical AND gate U4 output high level of while, drive radiator fan motor M, radiator fan opens and dispel