Automobile condenser electric fan controller

Claim 1

An automobile condenser electric fan controller installed in an automobile for automatically turning off a condenser electric fan of said automobile when a speed of said automobile surpasses a predetermined critical speed and for automatically turning on said condenser electric fan when said speed of said automobile below said predetermined critical speed, said controller comprising a working voltage source signal line connected to a battery of said automobile, a ground wire, a speed signal line connected in parallel to a speedometer of said automobile for providing a speed signal Ai, a compressor signal line connected in parallel to a low pressure switch of a compressor of said automobile for providing a compressor operating signal Bi having a high potential when said compressor is operating and a low potential when said compressor is not operating, an output control relay signal line, a filter for receiving a signal surpassing the predetermined critical speed reference signal Sth and converting the received signal into a corresponding DC level Ei, an inverted comparator for comparing the DC level Ei obtained from said filter with a reference DC level Vref and providing an output F according to the comparison result, said output F of said inverted comparator being at high potential when said DC level Ei is lower than said reference DC level Vref and being at low potential when said DC level Ei is higher than or equal to said reference DC level Vref, a first transistor connected between said inverted comparator and said output control relay signal line, and a second transistor connected between said first transistor and said compressor signal line, whereby said first and second transistor are electrically connected for turning on said condenser electric fan via said output control relay signal line when said output F and said compressor operating signal Bi both are at high potential, and said first and second transistor are electrically disconnected for turning off said condenser electric fan via said output control relay signal line when at least one of said output F and said compressor operating signal Bi is at low potential.