Motorola Corporation

Jerome Peter Friedrichs

Arnold Vincent Dano

Jerry James Tomaszewski

A unitary molded socket provides mounting for non-temperature compensated crystals, a resistor heating element for each crystal, and a thermistor. Each heating element is positioned adjacent a crystal housing for preventing the housing temperature from going below a given temperature. The thermistor is thermally coupled to one of the resistors for sensing its temperature and electrically coupled to control circuitry for providing the appropriate heating current to the resistor heating elements. A spring clip biases each crystal against its resistor, clamps it into the socket and is pivotable for replacement of components.

Thermally stabilized crystal mounting assembly

An oven having a thermistor controlled proportional heating system is compensated for ambient temperature variations by using a second thermistor sensing ambient temperature and connected in series with the control thermistor in an electrical bridge circuit. The control thermistor is mounted within the oven and substantially monitors the oven temperature while the ambient thermistor is located outside the oven and monitors ambient temperature. The electrical bridge circuit produces a temperature control error signal which is amplified and applied to a heater winding which is wrapped around the oven. The ambient thermistor produces a resistance variation in the electrical bridge circuit which modifies the temperature control signal such that a predetermined point inside the oven is held at a constant temperature regardless of any ambient temperature changes.

Growing community of inventors

Des Plaines, IL, United States of America

Jerome Peter Friedrichs