Other

Dinsmore Instrument Company

Gm Global Technolgoy Operations, Inc.

Hobart Corporation

Kelvin Shih

Peter A Hochstein

Robert C Dinsmore

Makram N Bishai

James M Dunford

Fu-Yih Shih

Kurt A Pochert

An instrument measures the LED junction temperature directly by taking advantage of the linear relationship between the forward current driven through the LED, the forward drop of the LED, and the junction temperature to determine the LED junction temperature. Calibration is conducted by placing two LEDs from the same family in ambient temperature and passing a small test current through each of the LEDs to obtain the forward drop of the LED at ambient temperature. The LED under test is then placed in an environmentally-controlled chamber where the temperature is raised a known amount above ambient temperature. Known low and high voltage values are associated with the ambient temperature and the environmental chamber temperature, causing the LED under test becomes a calibrated thermometer that can measure its own junction temperature due to the linear relationship between the forward drop and the junction temperature.

LED junction temperature tester

A light emitting diode (LED) designed to be used in conjunction with a heat sink includes an anode portion and a cathode portion formed from a thermally conductive material. The anode and cathode portions have a relatively large surface area to allow efficient heat dissipation. The cathode portion has a reflector cup formed thereon for supporting an LED chip. The LED structure allows the LED junction temperature to remain low, even as the LED chip is driven with higher currents, thereby allowing the LED to generate a higher light output without adverse temperature-related effects.

Light emitting diode with thermally conductive structure

A magnetic sensor for a magnetic anomaly detector includes a bobbin made from a layered printed circuit board material. A plurality of non-ferrous leads are attached to the bobbin for providing external connection to the sensor. A metal strip is attached to the bobbin. The strip is made from a material having a high permeability. First and second coils are wound around the bobbin and over the metal strip. The bobbin interconnects the first and second coils.

Magnetic sensor

A variable resistor/bar graph driver multiplexer uses a resistor network for obtaining a variable resistance and a constant current source. The resistor network contains a plurality of switches such that each switch corresponds with a particular resistor when depressed, thereby providing one of a plurality of output voltages. The output voltage is received by a receiver containing a bar graph driver circuit and a plurality of PNP drivers and relay coils corresponding to the switches at the transmitter. The relay coils will turn on depending on the switch pushed at the transmitter. This multiplexer circuit allows a large amount of switch position information and multiple to be transmitted over only two signal lines rather than the large number of lines used in conventional multiplexers. The multiplexer circuit can also be implemented using analog-to-digital converters and digital-to-analog converters at the receiver.

Multiplexer utilizing variable resistance, analog-to digital conversion,

A magnetic anomaly detector for detecting the presence of ferrous metal objects such as firearms, knives, or other weapons. The detector contains a square wave generator, a sensor for sensing ferrous metal objects, a sensor amplifier, a main amplifier, and a display. When a ferrous metal object is detected by the sensor, the resultant anomaly in the magnetic field causes portions of a pulse train being input to the sensor amplifier extend past a preset threshold, causing an average input value of an integrator to change. The integrator then forces the average input value of the waveform to zero over an extended period of time to compensate for the changes in the magnetic field. The value at the integrator input represents the magnetic anomaly. The anomaly is also visually displayed in an LED bar graph display for easy detection of weapons by the operator.

Magnetic anomaly detector for detecting the movement of ferrous metals

A fault tolerant communication system for transmitting a serial data signal through multiple wires regardless of whether one of the wires is open circuited, shorted to ground, shorted to a positive power supply. The system includes at least two communication lines. Each communication line is provided with identical data signals. The outputs of the communication line are adapted such that the active levels of each of the respective data signals appear within a predetermined voltage range. At least two detecting means are coupled to the communication lines. Each of the detecting means transmits one of the respective data signals only if the active levels of at least one of the respective data signals is within the predetermined voltage range. A fault is detected when the active level of any of the data signals is outside the predetermined voltage range. Combining means are coupled to each of the detecting means for combining the respective data signals from the detecting means into a single data signal. The combining means transmits the single data signal only if the active levels of at least one of the respective data signals is within the predetermined voltage range. The system ensures that the correct data signal will be transmitted despite a fault condition on one of the communication lines.

Ratio metric fault tolerant and redundant serial communication system

Provided is a magnetomoter apparatus for measuring low-level magnetic fields. The magnetometer utilizes a coil-pair wound on cores of a high permeability material. These coils are driven to magnetic saturation by an energizing circuit, and develop a uniquely shaped distortion spike in their back emf having an amplitude which is directly related to the ambient magnetic field. The resulting back emf of the coils can be compared and processed to generate a measurement of the ambient magnetic field.

Mirror image differential induction amplitude magnetometer

Provided is a magnetomoter apparatus for measuring low-level magnetic fields. The magnetometer utilizes a coil pair wound on cores of a high permeability material. These coils are driven to magnetic saturation by an energizing circuit, and develop a uniquely shaped distortion spike in their back emf having an amplitude which is directly related to the ambient magnetic field. The resulting back emf of the coils can be compared and processed to generate a measurement of the ambient magnetic field.

This invention provides an automatic current interruption to protect the audio power amplifier circuitry when current conditions above the capacity of the power amplifier are encountered. The circuit monitors the current supplied to the power amplifier and utilizes a transistor to interrupt power amplifier output. Power output is latched in its interrupted state until reset and is capable of quickly and effectively shutting down power supply output.

Power supply interruption circuit for an audio power amplifier

A method and circuit for supplying power from a constantly available power source (20) to an audio power amplifier (14) for a speaker (12) utilizing input leads (16,18) having an audio signal. A pre-amplifier (24) is used for amplifying the audio signal having a difference in potential between the input leads (16,18). A switch (58) powers the audio power amplifier (14) and pre-amplifier (24) from the power source (20) in response to a control signal. The method and circuit is characterized by sensing (26) the existence of a diminished audio signal by determining a greater difference than the predetermined difference between the input leads (16,18) to produce the control signal which operates a relay driver transistor (62) which, in turn, operates a relay switch (66) to supply power to the pre-amplifier (24) and power amplifier (14).

Audio transducer

An electrical timing circuit for controlling the activation and deactivation of an electrical load by setting a predetermined time period for which the load will be on and for providing one or more short warning periods wherein the load is deactivated prior to the expiration of the predetermined time period. The invention may be used as a switch for a light whereby the light may be actuated to remain on for an hour, but just prior to the expiration of hour period the light will momentarily go off for one or more warning periods prior to the light being turned completely off so that the switch may be reactuated to start another timing period. Momentary switches (12) control a set-reset circuit (16) which sends a signal to a NAND gate (18). A timing circuit (20) is responsive to the momentary switches (12) to provide a plurality of time spaced-signals. A first gate means (22) responds to the timing circuit (20) to provide an input to the summing gate (18) to effectively turn the load off, but only for short warning periods. A second gate means (24) is responsive to both the first gate means (22) and the timing circuit (20) to provide an input to the set-reset circuit (16) to effectively turn the load off at the end of the predetermined period.

Electrical timing control switch

An amplifier circuit for a speaker 12. The circuit includes an operational amplifier 16 connected to a supply rail 24 and a supply rail 26 through a regulator 28 and a regulator 30. The circuit is characterized by a P channel MOS-FET 32 having a source 34 connected to the rail 24 and a drain 36 connected to the speaker 12 and a gate 38, and an N channel MOS-FET 40 having a source 42 connected to the rail 26 and a drain 44 connected to the speaker 12 and a gate 46. A NPN stage 48 is responsive to the output 56 of the amplifier 16 for establishing a voltage differential between the gate 38 of the MOS-FET 32 and the rail 24 to drive the MOS-FET 32 into conduction. A PNP stage 50 is responsive to the output 56 of the amplifier 16 for establishing a voltage differential between the gate 46 of the MOS-FET 40 and the rail 26 to drive the MOS-FET 40 into conduction. The stages 48, 50 are connected to ground 52. A feedback circuit 94 interconnects the drain 36 of the MOS-FET 32 and the ground 52 side of the stage 48, and a feedback circuit 96 interconnects the drain 44 of the MOS-FET 40 and the ground 52 side of the stage 50. A feedback circuit 98 interconnects the speaker 12 and the amplifier 16 for returning a portion of the output voltage to the amplifier 16 to cause the output signal to track the signal at the input to the amplifier 16. A PNP transistor 68 has its base 72 connected to the source 34 of the MOS-FET 32 and its emitter 70 connected to the rail 24 and its collector 76 connected to the output 12, and an NPN transistor 82 has its base 84 connected to the source 42 of the MOS-FET 40 and its emitter 87 connected to the rail 24 and its collector 90 connected to the output 12.

Audio amplifier

An airflow sensor for a constant temperature anemometer comprises a copper foil resistor mounted on a polyimide foil which is supported in the airstream to be measured. The support preferably is a flat frame having an aperture over which the foil sensor is mounted so that the airstream can strike the sensor on both sides of the film. Airflow directors mounted upstream of the sensor are placed at an angle to direct the airstream toward each side of the film at a definite angle to obtain a positive cooling effect of the film by the airstream and consistent airflow. The sensor assembly is mounted in a duct with the plane of the sensor along the longitudinal axis of the duct for measurement of the flow through the duct. Another embodiment has a diamond shaped body mounted in an airflow such that a straight airflow impinges upon two forward sides of the body at a specific angle. A dielectric film mounted on the forward surfaces supports a metal film resistor on each face and a cavity in the body intersects the forward faces in the region of the metal film to isolate the film from the mass of the body to minimize the thermal mass of the sensor resistor element.

Mass airflow sensor

Delivery of a chemical sanitizing agent to the rinse system of a warewasher is confirmed by first sensing the absence and subsequently the presence of the sanitizing agent near the outlet of the delivery conduit. Failure to meet these two conditions in this order and within a preset time triggers an alarm to indicate delivery failure.

Sanitizer alert system

A power booster assembly for a transceiver including a secondary rechargeable battery which is charged by a charging circuit during the receive mode of the transceiver and is automatically switched into series with a primary power source to power the transceiver during the transmit mode. A switching circuit connects or switches the secondary battery into series with the primary power source. In a first embodiment of the invention a sampling circuit senses the presence of a radio frequency voltage during the transmit mode to accomplish the switching. In a second embodiment of the invention the sensing circuit is responsive to the power load of the transceiver during the transmit mode to accomplish the switching. An adjustable resistor compensates for the power load differentials between the transmit mode and the receiver mode for different transceiver designs in the second embodiment.

Growing community of inventors

Brighton, MI, United States of America

Kelvin Shih