Abstract:
The control circuit for an inverter is suitable for fabrication as an integrated circuit and includes, in addition to turn-on circuitry, protection circuits to assure reliable and automatic operation under abnormal circuit conditions such as overvoltages and low input voltages tending to cause device and power circuit failures. Voltage responsive sensors such as Zener diodes sense the appropriate voltages at selected points on the power circuit and modify the operation of the control circuit, preferably by over-riding and inhibiting the turn-on circuitry. Disclosed with regard to a one-thyristor, variable frequency series resonant inverter with an added maximum frequency control, the protection circuit technique is applicable to inverters generally.
Abstract:
An ultrasonic frequency induction surface cooking unit heats aluminum foil and other thin metal utensils placed on the cool cooking surface. For optimum heating the aluminum foil has a thickness of 0.5 mils. A uniform heating distribution is obtained by preferably using a rectangular induction heating coil with several series-connected elongated coil sections, or by varying the metal thickness to graduate the energy acceptance. Frozen convenience foods can be defrosted in this manner, and the aluminum foil can be wrapped about the food and shaped by the user into disposable utensils using a set of molds. Disposable foil cooking obviates the clean-up and storage problems of pots and pans.
Abstract:
Herein disclosed is an induction range having a counter on which there is rested a cooking vessel to be inductively heated by an induction coil having an air core; the induction coil being located below the counter. The counter has a passage therethrough extending from the top, or working, surface thereof, on which the cooking vessel rests, to a lower surface thereof near the induction coil. The passage in the counter and the induction coil''s core are in register. A bolometer is situated below the induction coil. The vessel rests on the working surface of the counter and covers the passage so that the bottom of the vessel is in an unobstructed line with the bolometer. The bolometer receives radiant heat energy from the inductively heated vessel and is instrumental in determining the temperature thereof.
Abstract:
Disclosed herein are various single wall and double-walled inductively heatable vessels for heating, serving and storing food. In general, each vessel is comprised of an inductively heatable inner part, or inner section, and an outer part, or outer section, which is not inductively heatable. For example, immediately after the vessel and food contained therein has been inductively cooked, or heated, on an induction appliance, the vessel may be rested directly on the surface of a conventional dining table without fear of burning the surface of the dining table and without fear that any of the diners will burn themselves by touching the outer part of the vessel. Such fears are abated because only the non-heated outer part of the vessel which is near room temperature touches the dining table and is safely accessible to the diners. The inductively heatable inner part, or section, of the vessel may be comprised of a vapordeposited metallic coating, metallic foil or sheet composite thereof, embedded powdered metal or coiled wires while the nonheated outer part or section may be comprised of suitable thermal insulation material such as plastics, glass, or ceramics, etc.
Abstract:
A metal oxide varistor body having an alpha in excess of 10 in the current density range of from 10 3 to 102 amperes per square centimeter is located so that it shunts laterally spaced electrodes across a discrete electronic circuit module. A dielectric may be located in the conduction gap between the electrodes. Either the electronic circuit module or the varistor body may be the substrate.
Abstract:
A method of cooking food using a recipe that specifies the absolute power level of an electronic range or appliance which inductively heats a cooking utensil. The power in watts generated by the electronic circuit driving an induction heating coil is a true indication of the power actually coupled to the utensil and used to heat the food. Induction cooking equipment for practicing the method requires only the addition of a wattmeter or other power measuring and indicating instrumentation. Adjustment to the desired watts setting can be manual or automatic.
Abstract:
Disclosed herein is an induction range having a counter including an undulant top surface for supporting a cooking vessel. Since the counter is made of a material which is not inductively heatable the counter remains relatively cool during the cooking process, while the vessel is being inductively heated. Although the counter''s top surface has undulations therein, it is, nevertheless, an unbroken surface; i.e., there are no openings therethrough. Moreover, even though the counter''s top surface has undulations therein, it may, nevertheless, be relatively smooth so that it can be wiped clean, easily. Furthermore, temperature sensing means are arranged on the top surface of the counter between adjacent undulations thereof and said sensing means are adapted to be contacted and easily compressed by the bottom surface of a vessel resting on the counter''s top surface; i.e., resting on the undulations.
Abstract:
Elements of metal oxide varistor material are integrally incorporated into the assemblies of switches such as breaker point assemblies and electric door bell assemblies to provide the dual functions of insulating the contact element supporting parts thereof and for limiting the voltages developed across the contact elements thereby minimizing arcing across the contact elements and consequent erosion thereof and electromagnetic radiation produced thereby.
Abstract:
A low cost opto-electronic transducer comprises a molded body of material having a pair of depressions therein. A semiconductor light source is located in one of the depressions and a photoresponsive device is located in the other. The molded body may comprise an opaque material, or, alternatively, the surfaces of the depressions may be coated with opaque material. This prevents direct illumination of the photoresponsive device by light emitted by the semiconductor light source. The depressions, and consequently the semiconductor light source and photoresponsive device contained therein, are closely spaced thereby eliminating any requirement for elaborate lens systems for focusing emitted or received light. The resulting product is a simple and inexpensive optical transducer for detecting objects at close ranges.
Abstract:
A power connector is provided with a body of metal oxide varistor material in conductive contact with each of the electrodes thereof. The metal oxide varistor material has an alpha in excess of 10 in the current density range of 10 3 to 102 amperes per square centimeter. The portions of the body in contact with the electrodes are spaced to provide a standby current flow which is low when normal operating voltage appears across the electrodes and when voltages in excess of the normal voltage appear across the electrode, a rapidly decreasing impedance is presented by the body in accordance with the alpha of the material of the body, thereby limiting the variation in voltage between the electrodes to a value close to the normal operating voltage.