Abstract: A system is provided wherein temperature conduction upon the changing of temperature of cooling water in an engine is forecast, and achievement of a cooling control system with an improved life and reliability and a reduction in cost results therefrom. A butterfly valve for regulating the flow of cooling water is rotatably controlled through a DC motor, a clutch mechanism 33 and a deceleration mechanism 33 so as to cool the engine at an appropriate temperature. A PWM signal generated by a quick response control and a PI control on the basis of at least load information of the engine is supplied to the DC motor 31 from ECU, whereby the butterfly valve 34b is rotatably controlled. A butterfly valve adjusting the flow of cooling water is controlled with the degree of valve opening by a thermo-element enclosing a thermal expansive body such as wax.

Abstract: A microwave alcohol fuel sensor comprises a microwave oscillator, a microwave receiver, and a microwave transmission circuit connected to the oscillator and the receiver. The microwave transmission circuit comprises a dielectric substrate and, a strip line mounted on the substrate so that microwaves leak from the substrate to an alcohol gasoline fuel, and the microwaves attenuate by alcohol dielectric loss, whereby output voltage from the receiver corresponds to alcohol content rate. The dielectric substrate is formed tubular so that a constant amount of the fuel is fed the sensor.

Abstract: A Doppler radar speed sensor including an antenna section and a sensor section is mounted on the underside of the automobile undercarriage. A recess for accommodating the Doppler radar speed sensor is formed in part of the underside of the automobile undercarriage within a rectangle surrounded by the wheels, and the Doppler radar speed sensor is mounted fully within the recess. This structure prevents the sensor from being damaged in an unfavorable environment or external vehicle devices from being interfered with by the leakage of the unrequired radar wave. For size reduction, the Doppler radar speed sensor is provided with a metal casing integrated with a slotted waveguide antenna. The slot array of the antenna is formed in one side of the metal casing, so that the metal casing, makes up part of the slot array antenna.

Abstract: A driving circuit for a brushless DC motor provided with an element for detecting the angular position of the rotor of the motor, characterized in that by the output of the differential amplifier for amplifying the output of the detecting element, a switching element is rendered on and off during a certain portion of the duration of the output of the detecting element and that the motor is rotated at a constant speed by applying a rotation control voltage to an element for energizing the stator winding of the motor during the non-conductive period.

Abstract: A transistor differential amplifier circuit includes a pair of NPN type amplifying transistors operated by a constant current source commonly connected to their emitters, and a pair of PNP type load transistors inserted in the collector circuits of said amplifying transistors, respectively. The load transistors are commonly biased with a constant voltage to operate within their saturation regions when input signals supplied on respective bases of the amplifying transistors are balanced, whereby pulse signals with a controlled duty ratio are obtained from the respective collectors of the amplifying transistors.