Abstract: A motorized power steering apparatus for a vehicle has a torque sensor which generates an output voltage proportional to a steering torque exerted by the driver of the vehicle and a supply voltage. A motor controller controls the output torque of a drive motor which generates an auxiliary steering force corresponding to the output voltage of the torque sensor. The supply voltage for the torque sensor is decreased as the vehicle speed increases, so that the output torque of the motor for a given steering torque decreases as the vehicle speed increases.

Abstract: A motorized power steering apparatus for a vehicle has a torque sensor which generates an output voltage proportional to a steering torque exerted by the driver of the vehicle. A motor controller controls the output torque of a drive motor which generates an auxiliary steering force corresponding to the output voltage of the torque sensor. A current limiter limits the motor current to a value which decreases as the temperature of the motor or the temperatures of power switching elements in the motor controller increases.

Abstract: A simple pulse width modulator speed control for a brushless DC "pancake" type fan motor utilizes a type 555 timer for driving a transistor switch, connected in series between the DC voltage supply and the fan motor, at about a 10 Hz rate. The duty cycle of the pulsed output of the timer is controllable by a variable resistor, which in the preferred embodiment comprises a thermistor for controlling the fan speed as a function of temperature. The fan motor is restarted on each cycle of full voltage amplitude pulses and consequently will start under all operating conditions.

Abstract: A DC power controller for controlling the rate at which direct current is furnished to a load. A signal generator provides a periodic signal having a first value during a first portion of each period and a second value during a second portion of the period. A switch such as a power MOSFET enables direct current from the source to flow through the load during the time the signal has one of said values and prevents the current from flowing during the time the signal has the other value. A control is manually operable to vary the relative durations of the first and second portions of each period and thereby control the rate at which electric power is furnished to the load. A plurality of MOSFETS may be arranged in parallel if the load draws more current than one MOSFET can safely switch. Surge and back EMF protection are provided for inductive or variable resistance loads.