Abstract: An integrated circuit device is disclosed for sensing dew point which uses integrated circuit techniques supported on a suitable substrate. Four semi-conductor junctions are used which are a Peltier junction or a junction capable of emitting or absorbing heat, a light-emitting junction, a junction that generates electrical current when exposed to light and a temperature sensing junction. The circuit cooperates to control time and switch the current through the Peltier junction to heat and cool it. The light-emitting junction emits light onto the reflecting surface. The light sensing means senses the reflected light, and the Peltier junction selectively heats and cools the reflecting surface causing moisture to condense on the surface which changes the reflecting properties of the surface and changes the amount of light to the light sensing junction. Current through the Peltier junction is then switched causing the Peltier junction to heat the reflecting surface evaporating the moisture.

Abstract: An educational device for teaching dental hygiene is disclosed. The device consists of a model of a human head having a mouth with teeth, moveable jaw and sensors imbedded in the teeth. A microprocessor is provided and the sensors are connected to the microprocessor. A probe and a toothbrush are connected to the microprocessor and may be held in the hand of an operator adjacent the teeth to simulate brushing, flossing, and other dental activities. Light emitting diodes of different colors are imbedded in the teeth and connected to the microprocessor to indicate conditions of the teeth. A speaker and a memory device are connected to the microprocessor to audibly discuss the procedures carried out with the information fed to the microprocessor from the teeth, and a command unit is provided to actuate the jaw to open and close the mouth.

Abstract: A constant horsepower drive system for a grinding wheel includes a first motor and associated control for rotating the wheel at a constant peripheral or surface speed and a second motor and associated control for providing linear relative motion between the wheel and a workpiece. Constant horsepower operation below the rated or base speed of the first motor is achieved by controlling the relative position of the wheel and the workpiece through the operation of the second motor. The control of the second motor is effected by the development of a correction signal which is a function of the quotient of a signal value representing the desired wheel surface speed divided by a second signal representing the counter electromotive force of the first motor.