Abstract: In order to improve a non-contact proximity switch, and a method for programming it, with an resonant circuit that can be influenced by objects approaching from outside and an evaluation circuit to generate an output signal as a function of an output voltage of the resonant circuit that exceeds a predefined threshold value, and with standard terminals, in such a way that the proximity switch can be used at different temperatures and operates accurately independently of the ambient temperature and independently of other trouble influences, it is proposed that a temperature sensor be arranged in the vicinity of the resonant circuit; and that a compensation circuit comprise a circuit unit, downstream from the temperature sensor, which outputs a compensation quantity, dependent on the sensed temperature, that is delivered to a comparator to be compared with the output voltage of the oscillator circuit and, when identity exists, to enable the output signal; and that the compensation magnitude for compensating for

Abstract: A system for distributing power from a detection switch parent device to detection switch child, or slave, devices. The system includes a power supply source for supplying an electric power; the detection switch parent device including, a body portion, an output wire for outputting a detection signal connected to the body portion, and power supply wires connectable to the power supply source, for receiving the electric power; at least one detection switch child device each including, a body portion, and an output wire for outputting a detection signal connected to the body portion; and electrical connection means for electrically connecting the body portions of the detection switch parent device to detection switch child device to one another to transmits the electric power being supplied to the body portion of the detection switch parent device to the body portion of the detection switch child device.

Abstract: A system and process for control of energy use in a rented room based on direct occupancy observation. The system is designed to control up to 100% of the power usage. The system includes: a power supply; occupancy sensors; a thermostat responsive to a predetermined signal; electrical outlet receptacles and/or switches that are responsive to a predetermined signal transmitted over the powerline; and a central interface unit for receiving signals from the occupancy sensors and, based on the signals received from the occupancy sensors, controlling power consumption by the thermostat and electrical outlet receptacle and/or switches. The system can be used in a process for improving energy efficiency by direct observation of occupancy of an area in multitennant facilities, such as hotels, that has a plurality of discrete living quarters.

Abstract: An earthquake escape light system having several different triggering systems. In one system vibrations are sensed as several steel balls move between two plates with the upper plate being connected to an upright member. At the lower end of this upright member is a steel ball normally electrically insulated from a lower conducting surface. Vibrations will cause the steel lower ball to contact the lower conducting surface and complete an electrical path to a light source. Alternately, the upper plate may have an arm with a hook end attached to it. This end restrains a pivotally mounted tube with mercury within from completing an electric circuit to a light source. When vibrations occur the hook comes off to complete the circuit. In another embodiment two magnets normally equally attract the free end of a electrically connected spring. When this end is subject to vibrations one of the magnets attracts it to complete a circuit to a light source.

Abstract: Contention free switches, networks and global interconnection systems for routing messages from N input sources to M output destinations are disclosed.

Abstract: A method of achieving a comfortable temperature in the surroundings of a person, who is present in a room of low temperature, by means of a radiator is quickly reached and continuously maintained by continuously measuring the temperature in the surroundings of the radiator (18). While a direct thermal influence of the radiator is avoided, or the measurement is avoided, a required irradiation for the person is calculated from the temperature data by an electronic unit. The distance between the person and the radiator is measured, and the required power is provided to the radiator (18) in accordance with the calculated irradiation and the measured distance.

Abstract: The add-on smart socket adaptor integrates electric facilicities and/or home appliances to be an intelligent system for the home automation. The add-on smart socket adaptor has the add-on multiple different sensors to detect the complex environmental changes as the inputs of the programmed logic to make the complex decision function to generate the output to turn on and/or turn off the multiple different home appliances and electrical facilities smoothly, separately and cooperatively. The add-on smart socket also can be built-in to integrate with the home appliances and electrical facilities to have the home automation. The add-on smart socket adaptor provides the open platform and standard for the synthesis of home automation integrated system.

Abstract: A two wire detection device includes a relay switch setable to a high and a low impedance state and electrically coupled between a first terminal of an AC source and a first leg of a load, a second leg of which is connected to a second terminal of the AC source. The device includes an energy storage device electrically coupled to the first terminal of the AC source and electrically connected to the first leg of the load. Charge control means interposed between the first terminal of the AC source and the energy storage device regulate the voltage across the energy storage device. A detection control device is electrically connected across the energy storage device and to the switching device for detecting the presence of a condition for monitoring and setting the state of the switching device based thereon such that power is available to the detection control device regardless of the state of the switch.

Abstract: A multifunction passive infrared occupancy sensor functions as an occupancy sensor for security systems and also as an occupancy sensor for energy management control systems. The occupancy sensor comprises at least one segmented infrared lens array wherein the segments of the infrared lens array establish different optical lobes in the field of view of the occupancy sensor. At least one pyroelectric infrared detector is positioned at or near the focal point of the segmented infrared lens array, for detecting movement of infrared sources within the field of view of the occupancy sensor and producing an output signal representative thereof. A processing means analyzes the output signal of the detector for security detection purposes by detecting changes in the output signal greater than a given security threshold.

Abstract: A method and apparatus for adjusting the clock frequency and voltage supplied to an integrated circuit. First, a signal is sent to the clock, and in response, the clock lowers the clock frequency supplied to the integrated circuit. The clock sends a signal to the voltage regulator whereupon the voltage regulator reduces the voltage supplied to the integrated circuit.

Abstract: A switch including a mass suspended above a base by a flat horizontal spring has electric contacts that close in response to the initial shocks of major earthquakes and activates safety devices before the onset of destructive ground motions. The vertical unidirectional seismic switch can be manufactured by micromechanical photolithography and is integrated with electromechanical safety devices to latch cabinets closed, secure movable objects, shut off gas, water, and electric utilities, activate alarms, early warning networks, and related automated response systems. The device is fully self contained, consumes no power until activated, is inexpensive to produce, and impervious to nonearthquake noise in that it is designed to respond specifically to the vertical acceleration and displacement characteristic of the initial shock waves of a major earthquake.

Abstract: An electrical load, such as a motor, has a first and a second terminal element for supplying electricity to the load. The second terminal element is directly connected to the load whereas the first terminal element together with a further terminal element forms a clamping socket for a switching device. The further terminal element is electrically connected to the load. When the switching device is inserted into the seat, the first terminal element is connected to the load in series with the further terminal element via the switching device.

Abstract: Apparatus is disclosed for preventing injury to an occupant of an enclosed space as the result of exposure to a noxious gas. The apparatus shuts a source of noxious gases, when an unsafe ambient condition is sensed. More particularly, the unsafe condition is typically the presence of the noxious gas in the enclosed space. In some forms of the invention the apparatus also includes structure for latching that upon sensing an unsafe condition continues to send a signal to shut off the source of noxious gas. Some forms of the apparatus may further include an override for the latching aspect of the structure. The override may be a manually operated push button that operates a relay. The apparatus for shutting down the source of noxious gases is a relay in some forms of the invention and that relay may be normally closed in some embodiments.

Abstract: A method and apparatus for reducing bloom in output of a charge coupled device (CCD) image sensor is disclosed. The method includes the step of toggling at least two phases of said CCD after exposure of said CCD. The method and apparatus are particularly useful when a flash of light occurs during the exposure.

Abstract: A starter comprising a contactor with an overcurrent relay provides an appropriate cooling interval for each of multiple classes of a load, such as a motor. An analog equivalent of a digital I.sup.2 t value calculated by a microcomputer in the overload relay is maintained by an external capacitor. When the microcomputer loses power following a trip, the capacitor discharges through a resistor at a rate selected to mimic cooling of the associated class of the load. Restart of the load is prevented until the appropriate interval, represented by the time required for the voltage on the capacitor to decay to a common reset value, has expired. The capacitor is charged to a voltage proportional to the I.sup.2 t trip value for the particular class of the load, which for all classes is below the forward drop of the clamping diodes on the microcomputer inputs to prevent discontinuities in the timing.

Abstract: A manually actuatable integrated pilot light/contact/communications module connecting to an associated output device also having a communications module by means of a common communications link. The integrated pilot light/contact/communications module has at least one electrical contact, a logic circuit, a communications circuit, a communications terminal and pilot light activation circuit mounted on a printed circuit board. A bulb base for a pilot light is mounted on the module enclosure and electrically connected to the printed circuit board. The printed circuit board provides communication between the electrical contact and the logic circuit, between the logic circuit and the communications circuit, between the communications circuit and the communications terminal, between the communications circuit and the pilot light activation circuit, and between the pilot light activation circuit and the pilot light. The printed circuit board is enclosed within the module housing.

Abstract: A motion sensor and photoelectric light sensor activated plug-in type electrical receptacle which conveniently plugs into a standard power outlet is disclosed. The device allows non-motion detector and/or non-photoelectric equipped devices to function as motion sensor and/or photoelectric sensor operated devices. The device has motion and photoelectric switches permitting customized applications. The device can be used with any wall or ceiling mounted electrical outlet to automatically turn on and off other plug-in type electrical devices such as night lights, radios, heaters, and thereof, when presence of people and/or pets is detected. This device conveniently plugs into any wall power outlet by means of two or three prongs without requiring new wiring or rewiring of the existing electric circuit.

Abstract: A windshield heating system includes a heating element installed in the defroster ductwork of a motor vehicle. An electrical driver provides electrical power to heat the heating element, thereby immediately providing heated air to the windshield of the vehicle when the vehicle is started in cold weather. The electrical power provided to the heating element can be modulated based on (1) temperature of the air before the heating element, (2) temperature of the heating element, and (3) system voltage of the vehicle.

Abstract: A self-configuring photoelectric control circuit for controlling operation of a load based on ambient light. The photocontrol circuit comprises a photocell responsive to ambient light, a heating resistor connected to the photocell, a bimetallic element in proximity to the heating resistor and movable in response to generation of heat from the heating resistor. A switch is operated by the bimetallic element and is connected between an input connected to a power source and an output connected to the load. A series resistor is connected to the heating resistor and a shunt is connected across the series resistor to provide a current bypass around the series resistor for operation with a low voltage power source, for instance 120 volts. The shunt is maintained in a flexed condition to form the bypass and a connection of the shunt across the series resistor is formed of a meltable material.

Abstract: The first zero crossing of the power signal, after the detection of an opening/closing signal, initiates a series of predetermined, timed, steps which reduces or eliminates the overvoltage after opening/closing a circuit breaker on a high power line.

Abstract: A two wire detection device includes a relay switch setable to a high and a low impedance state and electrically coupled between a first terminal of an AC source and a first leg of a load, a second leg of which is connected to a second terminal of the AC source. The device includes an energy storage device electrically coupled to the first terminal of the AC source and electrically connected to the first leg of the load. Charge control means interposed between the first terminal of the AC source and the energy storage device regulate the voltage across the energy storage device. A detection control device is electrically connected across the energy storage device and to the switching device for detecting the presence of a condition for monitoring and setting the state of the switching device based thereon such that power is available to the detection control device regardless of the state of the switch.

Abstract: A driver or ballast for the ultraviolet bulb of a water treatment system. The driver includes a step-up transformer and a feedback oscillator connected between the secondary and the primary of the transformer. The secondary of the transformer also is selectably connected through one of two different capacitor compensators depending on water flow through the system. In a low intensity mode, the current and the power factor output of the driver are relatively low--preferably just enough to keep the bulb filaments energized. In a high intensity mode, the current and the power factor are relatively high to power the bulb at a relatively high efficiency. The driver operates at a relatively low DC voltage. A voltage converter selected as function of the local line voltage converts the AC line voltage to the necessary DC voltage.

Abstract: A frequency slider circuit for reducing power dissipation in the form of switching losses in a switching device when the switching device is near its desired maximum temperature limit is disclosed herein. The switching device controls an electric load, such as a motor. The frequency slider circuit samples a current of the switching device. The frequency slider circuit then uses a current transducer to convert the current to a signal level. The signal level is then processed by a model of the thermal response of the switching device. The output of the thermal model is compared to a reference signal, and if the output of the thermal model is greater than the reference signal, the switching frequency of the switching device will be lowered gradually to keep the power generated during the switching periods to be below a predetermined value. A minimum frequency clamping circuit is included to ensure that the switching frequency never drops below a minimum value, to ensure stable operation of the switching device.

Abstract: A photoelectric converter comprising a photosensor element, a typical example of the photosensor element comprising: a transistor including an n or n.sup.+ collector region an n.sup.- region disposed contiguous to the collector region, a p base region disposed contiguous to the n.sup.- region, an n.sup.+ emitter region disposed contiguous to the base region, and a first electrode connected to the emitter region; and a storage capacitor constituted by the base region, an electrically insulating region disposed contiguous to the base region, and a second electroce connected to the electrically insulating region; whereby the base region is held in a floating state. A photogenerated is stored in the base region by controlling the potential of the base region and an electric signal corresponding to the charge stored in the base region is subsequently output from the first electrode.

Abstract: A housing supports a seismically responsive switch mechanism having an annular contact ring defining a center aperture within which a contact weight is resiliently supported by a flexible spring rod. A silicon-controlled rectifier is operatively coupled to a DC power input and power output coupling to provide electrical power coupling therebetween when the silicon-controlled rectifier is triggered. The trigger voltage for the silicon-controlled rectifier is provided by a circuit path which includes the annular ring and contact weight. The contact weight defines a frusto-conical outer surface and a ring positioning apparatus supports the ring at different positions with respect to the contact weight to provide different distances between the contact weight and the ring. In one embodiment, the ring positioning apparatus includes a rotatable shaft and a gear coupling which drives a threaded support to raise or lower the contact ring with respect to the contact weight.

Abstract: The present invention generally relates to a cost-effective photocell switching circuit which can be manufactured as a single, factory sealed unit suitable for use in Class I, Division 2 environments. In accordance with the present invention, the switching circuit can be wholly formed with electrical components (i.e., without movable parts such as electro-mechanical relays). Further, features of switching circuits designed in accordance with the present invention render the electrical components immune to noise such that the components can be combined in a single unit, explosion-proof housing, thus reducing overall switching circuit complexity and production costs.

Abstract: An intelligent wall switch incorporates a passive infrared sensor and a pressure pulse-wave sensor. A microcontroller monitors the sensor signals generated by the infrared sensor and the pressure pulse-wave sensor and calculates a weighted sum of the signals generated by the sensors. If the weighted sum calculated by the microcontroller exceeds a preset threshold the intelligent wall switch generates a signal indicative of human presence.

Abstract: Fire control systems and release mechanisms. The release mechanisms of the present invention comprise a digital logic circuit for processing signals which are indicative of a condition in an outside environment, and for providing a trigger that will actuate the mechanical release mechanism in response to the condition, a power circuit for providing regulated power to the electronic circuit in response to the input power, the regulated power being used to operate the digital logic circuit, and a power backup circuit interfaced to the power circuit for providing the regulated power for a predetermined time in the event of an input power failure so that the digital logic circuit can be operated for the predetermined time during the input power failure.

Abstract: A compact photosensor circuit provides automatic intensity range control for machine vision systems. The circuit may be implemented with standard CMOS integrated circuit technology to provide high sensitivity, fully static operation, and automatic exposure control with no moving parts. For each pixel of an imaging array, a photodetector provides an input photocurrent to a corresponding photosensor circuit. The photodetector is connected to provide an output voltage and an input to the gates of a pair of series-connected FETs that act as an attenuator. The attenuator is connected to a biasing source that provides a floor bias voltage. An output of the attenuator is connected to the gate of a third FET connected to the input photocurrent. The output voltage responds as a function of the light intensity at the photodetector while the bias voltage determines the range of light intensity for normal operation of the photosensor circuit.

Abstract: A control circuit for a stove, cooktop or oven utilizing at least one electrical radiant heating element. The circuit effectively compares a controlled voltage and internally generated saw-tooth voltage wave to control the percent power to the radiant element. Also included is a slow start feature to minimize power surge when first energizing the element.

Abstract: A photoelectric converter is adapted for an accumulation operation, readout operation and refresh operation. The photoelectric converter includes a transistor including a control electrode region having a semiconductor of a first conductivity type, a first main electrode region comprising a semiconductor of a second conductivity type different from the first conductivity type and disposed electrically connectable to an output circuit including a capacitive load, and a second main electrode region of the second conductivity type, the control electrode region being adapted for accumulating carriers in response to light energy received. Refresh is provided for extinguishing the accumulated carriers while holding the first main electrode region at a reference potential during the refresh operation after the readout operation for reading out a signal based on the accumulated carriers.

Abstract: A safety device for machine tool operators has a generator for RF signals, an antenna connected with the generating means for receiving the generated signals, and positionable in the vicinity of a working zone of the machine tool to supply the signal to the working zone, an and element to be worn by an operator and providing a delayed version of the RF signal when the element is located in the vicinity of the antenna. An RF signal receiver is connected with the antenna and receives the delayed RF signal supplied by the element, a blocking unit is connected with the receiving means and blocks a machine tool drive when the RF signal delayed by the element worn by the user is received by the receiving means.

Abstract: Ultrasound imaging system providing automatic activation of a probe, which ultrasound system includes: (a) a motion sensor for detecting motion of the probe and for generating a signal in response to the motion; (b) a signal detector for detecting the signal; and (c) a probe activator, in response to a detector signal from the detector, for activating the probe. In a preferred embodiment of the present invention, the motion sensor is an accelerometer which is affixed to the probe.

Abstract: A device for control and monitoring of pressure in a system combines a conventional three pole pressure switch with the following additional features: (1) a lock mechanism with three influencing input factors and a single resulting output contact action, (2) a three pole thermal release device as one of the input factors, and (3) a remote control tripping device as another input factor, all integrated into a single, compact, modular unit. The thermal release device comprises a plurality of bimetals which sense electrical flow passing through the device, and which are mechanically connected to a locking mechanism to shut off current if the electrical flow reaches a predetermined maximum. If any of the three inputs activates the locking mechanism, the device must be reset by an operator.

Abstract: An electrical circuit for use in occupancy detectors for preventing false triggering when a load such as a light is de-energized. The occupancy detector includes circuitry for providing an intermediate signal indicating detection of a target object. An output stage receives the intermediate signal and in response provides a trigger signal for energizing the light or other load. An RC network, having a characteristic charge decay time, is coupled to the output stage such that the characteristic charge decay time governs the duration for which the output stage asserts the trigger signal for energizing the light or other load. Output signals from the occupancy-detecting circuitry are applied to the RC network through a first transistor switch. A second RC network, having its own characteristic charge decay time, is provided and the trigger signal is applied to charge the second RC network.

Abstract: A photo SI thyristor driving circuit which has a good switching characteristic suitable to be used for a photo relay, and a protection circuit therefor for protecting a photo SI thyristor element from being broken down due to a thermal runaway. The photo SI thyristor driving circuit comprises a photo SI thyristor, a MOS transistor provided in a gate circuit of the photo SI thyristor to draw charges accumulated at the gate of the photo SI thyristor when the photo SI thyristor is turned off, and a plurality of photo electromotive force elements provided in a gate circuit of the MOS transistor to generate a photo current for biasing the MOS transistor. The protection circuit includes a snubber circuit connected between the anode and the cathode of the photo SI thyristor and a light emitting element for irradiating light to the photo electromotive elements in response to an output from the snubber circuit.

Abstract: A high sensitivity control circuit for a solid-state relay is disclosed for use in optically coupled solid state relay circuits having a light emitting diode. The control circuit reduces a loading effect of the turn-off circuit on a photodiode array allowing the photodiode array to operate the switching transistor to switch an input signal to a switching contact. A two stage CMOS transistor circuit acting as an amplifier is employed for high-speed switching. Deactivation of the light emitting diode reverse biases a sense photodiode to discharge the switching transistor to prevent switching of the input signal to the switching contact.

Abstract: A range extender module for extending the range capability of a barrier control system comprising a low voltage AC control unit which receives low voltage AC control signals conveyed by wires to input terminals thereof from a plurality of remotely located switches and responds to such AC control signals by controlling the barrier. The controlled barrier may be, for example, a garage door or a driveway gate. The range extender module is inserted into the wires between the low voltage AC control unit and the remote switches and includes a source of DC voltage, which is used to energize the formerly AC energized switches and responds to DC input signals created by operator interaction with the switches by selectively gating low voltage AC control signals to appropriate input terminals of the low voltage AC control unit for controlling the barrier.

Abstract: An amplification-type photoelectric conversion device utilizes a JFET and is capable of amplifying charges generated by photoelectric conversion with a high amplification factor and improves the S/N ratio. The device is provided with a drive circuit for respectively applying driving signals to a source region, a drain region and a gate electrode of the JFET. The drive circuit has a first signal mode for accumulating charges generated by incident light on the JFET, and a second signal mode for causing the flow of current between the source and the drain and raising a potential difference between the source and the drain to a high level thereby causing an impact-ionization effect corresponding to an amount of the charges accumulated by the first mode to accumulate the resulting charges. A signal output corresponding to a total amount of the charges accumulated by the first and second modes is delivered from the drain.

Abstract: A safety device for breaking power supplied to the plug of an appliance cord from a standard, preexisting electrical receptacle. The device plugs into the standard receptacle, and in turn accepts the plug of the appliance in an exposed corresponding receptacle. The device detects an audible alarm signal from a standard, preexisting smoke detector, and operates an automatic switch provided in the device. The automatic switch interrupts a power circuit which normally conducts power from the preexisting receptacle to the corresponding receptacle provided in the safety device. A control circuit operates the automatic switch responsive to detection of the audible alarm. An alarm condition indicator and manual reset are provided. The device is compact and unobtrusive, plugs manually into the preexisting receptacle, and requires no modification to the preexisting receptacle, smoke detector, or appliance in order to operate automatically.

Abstract: A shock sensor includes a mass suspended in a flexible support arranged to resonate when subjected to a mechanical shock, a microphone spaced closely to the mass, the mass and microphone forming a first air pressure chamber with the flexible support for transmittal therethrough of air pressure waves from the resonating mass to the microphone, the microphone arranged to produce an electronic signal when it detects changes in air pressure from the pressure waves traveling through the chamber.

Abstract: A two-way conductive directional circuit formed in a polycrystalline silicon layer separated by an insulation film from a semiconductive element is one-way biased for sensing a temperature of the semiconductive element. The directional circuit may be provided with a bias in either conductive direction thereof for sensing a temperature of the semiconductive element, before being provided with a bias in the other conductive direction thereof for sensing the temperature of the semiconductive element.

Abstract: The invention relates to a method for automatic switching and control of lighting to a localized area, the switching of the lighting being dependent on the presence or absence of a person in that localized area and the control of the lighting intensity being dependent on the sensed background level of lighting in that localized area. The invention also relates to a lamp fitting and to an automatic control device for controlling the light output of a light source in a "self managed" and "self controlled" energy saving luminaire.

Abstract: A counter cell includes a latch circuit, control circuit, and a pull-up circuit. The latch circuit is formed of a first clocked half-latch, a second clocked half-latch and an inverter for storing a binary output signal. The first clocked half-latch is responsive to a first clock phase signal for transferring the binary output signal from its input to its output. The second clocked half-latch is responsive to a second clock phase signal for transferring a binary output signal from its input to its output. The control circuit is responsive to an input complement signal for selectively passing the first clock phase signal to the first clocked half-latch so as to permit toggling the state of the binary output signal. The control circuit requires only one transistor and two input signals to perform its required functions. When the input complement signal is High and the first phase input clock signal is High, an enable signal is sent to the first clocked half-latch, thereby enabling the count process.

Abstract: An improved temperature control system for a power conversion circuit having two or more power converters operating in parallel and providing output power to a single load. The temperature control system maintains the temperature of each of these power converters at approximately the average temperature of the power converters. A detector coupled to each power converter detects the temperature of the power converter and generates a measurement signal that is a function thereof. A reference signal is generated that is a function of each measurement signal. A control circuit responsive to the measurement signal of each power converter adjusts the output power of that respective converter as a function of the difference between that converter's measurement signal and the reference signal such that the temperature of each power converter approximates the average of temperature of the power converters.

Abstract: A pressure activated switch is positioned for actuation of a horn in the steering wheel of a motor vehicle. The switch is mounted on an airbag cover and generates a signal when the switch is activated by the deflection of the cover. A temperature sensing device is positioned on the cover for generating a signal indicative of the cover temperature. The temperature signal is utilized for changing the actuation pressure or deflection required on the pressure or deflection activated switch to compensate for changes in cover stiffness due to the temperature changes of the cover. The invention is thus directed to providing a consistent horn actuation force regardless of the temperature of the airbag cover to which such force is applied to actuate the horn of the motor vehicle.

Abstract: A temperature regulating control system for an oven of a cooking apparatus and methods of making and operating the same are provided, the system having a circuit for interconnecting a power source to a load of the apparatus in a regulated manner so as to tend to provide a selected temperature output of the load for the oven, the circuit comprising a microcomputer, external components, and a voltage regulator for providing a regulated voltage from the power source for operating the microcomputer so that the microcomputer can operate the external components, the circuit having a temperature sensing unit to sense the ambient temperature of a portion of the circuit and provide a warning signal to the microcomputer that a first high ambient temperature has been sensed so that the microcomputer can shut down the external components of the system in a controlled manner before a second higher ambient temperature is sensed by the temperature sensing unit.

Abstract: A control unit for switching AC powered high efficiency lighting in response to a signal from an occupancy sensor. The lighting is switched by a hybrid mechanical relay/semiconductor switch. The semiconductor switch is connected in parallel with the relay switch contacts to protect them and is controlled by a noise-insensitive zero voltage crossing detector circuit which switches the semiconductor switch only at the zero crossings of the AC power. The semiconductor switch is preferably turned on by a pulse forming circuit only for a brief period of time spanning the time when the relay is switching.

Abstract: A phototransistor is provided with a first resistor that operates as a shunt and a second resistor that operates to protect the device from damage that could be caused by a reverse bias condition. The possible damage results from the creation of a PN junction relationship caused by the doping of N conductivity type material with P.sup.+ conductivity type material in order to form the first resistor. This junction relationship creates a parasitic diode that provides a current path between the emitter and collector terminals of the phototransistor. In order to prevent damage that might occur during a reverse voltage connection, a second resistor is connected between the emitter of transistor Q.sub.1 and the first resistor. The second resistor is in series with the junction relationship resulting from the structure used to form the first resistor and therefore serves to limit the current flowing between the emitter and collector terminals of the transistor under reversed bias conditions.

Abstract: An anti-abuse circuit and method is described for shutting down a load wherein the load is connected to a controller having a predetermined range and demanding operation of the load through a relay until the predetermined temperature range is achieved. The anti-abuse circuit is positioned between the controller and the load. The anti-abuse circuit controls the relay when a demand signal is present indicating the operation of the load. The anti-abuse circuit energizing the relay during the predetermined time period and receipt of the regulated demand signal. The anti-abuse circuit de-energizing the relay when either the predetermined time period expires or the regulated demand signal stops.