Emhart Industries, Inc.

P. R. Mallory Co.

Mallory Components Group Emhart Industries, Inc.

Walter R Spofford

Charles E Scott

Daniel I Pomerantz

Louis M Sandler

Sanders Goldstein

The temperature probe is biased for causing current flowing therethrough to be proportional to the probe temperature. A variable set point temperature is represented by a variable reference current which is summed with the temperature probe current. An output signal is produced therefrom to indicate the relationship between the set point temperature and the probe temperature.

Temperature sensing circuit for semiconductor junction temperature probe

An oscillator circuit having a variable duty cycle for controlling the power level of a microwave oven provides an adjustable RC time constant circuit including a capacitance branch and a resistance branch and coupling means therebetween, the resistance branch including a pair of alternately selectable current paths for the charging and discharging of the capacitance branch, the coupling means including semiconductor switch means for selecting and coupling either of the current paths to the capacitance branch for changing the charging and discharging of the capacitance branch in accordance with the selected current path, and one of the current paths including a pair of parallel connected portions with each of the parallel portions having a diode connected therein for controlling the direction of current flow, the diodes being connected with opposite respective polarities for allowing current flow only in opposite directions in the respective portions, the one current path further including a potentiometer having a pair of fixed terminals each of which is connected to a separate parallel portion and a variable wiper terminal connected to the first coupling means for simultaneously inversely varying the resistance in the parallel portions.

Oscillator circuit for controlling the power level of a microwave oven

A touch control system includes at least two capacitance means, a shunting means, and an implemental means wherein the implemental means includes at least two multiple input inverting logic gates having complementary metal oxide semiconductors (CMOS).

Implemental means for a touch control system

A circuit for controlling the application of alternating current power to an apparatus provides a triac having a pair of main terminals adapted for being coupled in series between the apparatus and a source of alternating current power, the triac also having a gate terminal, nonregulated direct current power supply adapted to receive alternating current power from the source thereof, the power supply including a rectifier and a filter and having a pair of output terminals for distributing direct current power, circuitry for maintaining an approximately constant load on the nonregulated direct current power supply and for switching current therefrom to the triac gate terminal including a semiconductor junction switch having a gate terminal, a first main terminal coupled to one output terminal of the power supply and the triac gate terminal and a second main terminal coupled to the other output terminal of the power supply, and circuitry coupled to the switch gate terminal for activating and deactivating current flow in the switch to deactivate and activate, respectively, current flow through the triac by shunting current from the one terminal of the power supply away from the triac gate and to the other power supply terminal, thereby providing control of the application of alternating current power to the apparatus.

Alternating current power control circuit

Disclosed is a control system for controlling the operation of an appliance and the like which is particularly adaptable for controlling at least one operation variable of an apparatus for drying articles such as a clothes dryer, washer-dryer or similar type of appliance. The drying apparatus is capable of accurately drying any number of articles to a desired degree of dryness irrespective of time by sensing a plurality of temperatures and deriving a final temperature difference for each load of articles indicative of the degree of dryness desired. Furthermore, the control system provides the ability to optionally control the drying apparatus by timing its operation, to control the temperature of the air used for drying, to reduce the temperature of the air used for drying before the completion of an operation cycle so as to avoid setting wrinkles, and to determine and indicate when excessive lint has accumulated on the lint filter. The control system includes a control element for processing a plurality of signals representing programmable values of operation variables and representing varying conditions associated with the operation of the appliance in accordance with a control strategy, means for addressing the control element with such signals, and means for activating and deactivating the appliance in accordance with the control strategy.

Means and method for controlling the operation of a drying apparatus

A thermistor temperature sensing system includes a conventional comparator having a constant reference threshold voltage and a linearized thermistor sensor which in combination detect a limited range of desirable temperatures. A means is also disclosed for extending the linearization of the thermistor in a piecewise manner at at least one temperature extreme where linearity typically severely deteriorates. In a thermistor temperature sensing system, linearization of thermistor characteristics with respect to at least one temperature within the temperature extreme is achieved by utilizing circuitry which makes the threshold voltage of the conventional comparator a function of the setting of a potentiometer for a desired temperature within the temperature extreme to be sensed by a thermistor sensor. The piecewise linearization technique disclosed allows easy interface with the thermistor temperature sensing system for detection of an optimum of selectable temperatures in the extended range of linearized characteristics of the thermistor.

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Bedford, MA, United States of America

Walter R Spofford