Abstract: A glass-ceramic cooktop surface is provided with a temperature sensor integral with the glass ceramic plate of the cooktop. The temperature sensor utilizes the temperature resistance characteristic of the glass ceramic plate as a means of monitoring the temperature of the plate and is formed in the heated areas of the glass-ceramic plate. The sensor comprises pairs of metallized conductive strips fired to the underside of the plate and terminated in a cool region of the plate. A continuity resistor is provided at the termination point of each pair of strips to distinguish between cold glass conditions and a defective sensor. One strip of each pair is connected to a further metallized strip which surrounds the periphery of the glass and forms a common ground for a heating unit control circuit and is also used as a broken glass detector. Each sensor forms one leg of an AC voltage divider and is connected to an associated control circuit.

Abstract: A user input/output device comprises a lighted, segmented bar graph type display and an array of light transmitting touch sensitive areas superimposed over the bar graph display. A suitable circuit means is responsive to the touch sensitive areas and connected for driving the segments of the bar graph such that when any one of the touch sensitive areas is touched, a corresponding display segment and all display segments to one side are energized and the remaining display elements are de-energized.

Abstract: A self-contained, temperature responsive alarm control circuit uses a battery as an energy source. A solid state, free-running multivibrator provides a square wave of audio frequency which provides the pulse to turn on an emitter follower also at an audio frequency so as to energize a Wheatstone bridge across the battery at the same audio frequency. One of the legs of the Wheatstone bridge includes a temperature sensitive thermistor. A programmable unijunction transistor serves as a threshold detector for the bridge circuit which, upon its being gated into conditon upon the reaching of a predetermined, preset temperature sensed by the thermistor, provides a signal to turn on an audio amplifier at the same audio frequency thereby to energize a speaker now essentially coupled across the battery to produce an audible sound.