Abstract: An system is provided for testing emergency lighting units using a receiver connected to the emergency lighting unit and a portable transmitter operable remotely with respect to the emergency lighting unit. The emergency lighting comprises a transfer relay for switching a battery between a primary power source and a lamp. A TEST button and the receiver each include a normally closed contact switch connected in series with each other, as well as with a primary power source input and transfer control circuitry. The transmitter generates encoded signals for wireless transmission to the receiver as long as a control switch on the transmitter is being activated by a user. The receiver receives and decodes the encoded signals and opens its normally closed relay as long as encoded signals are being received, causing the transfer control circuitry to activate the transfer relay to switch the battery from the primary power source to the lamp.

Abstract: A control unit for controlling a strobe light or the like, in particular for use in an alarm system or an emergency locator, is characterized in that a direct current power supply unit is provided which is activated to drive the strobe light when an external power supply unit which is adapted to drive the strobe light is deactivated.

Abstract: A reference light source device includes a first laser diode emitting a reference light, a harmonic generating unit for generating an nth harmonic of the reference light, where n is an integer, a light generating unit for generating a light signal having a waveform equal to that of the nth harmonic of the reference light, and a photodetector for combining the nth harmonic and the light signal and for generating a first electric signal corresponding to a beat signal obtained by combining the nth harmonic and the light signal. Further, the source device includes a local signal generating unit for generating a local signal, a phase comparator for generating a control signal corresponding to a phase difference between the first electric signal and the local signal, and a driving unit for driving the first laser diode according to the control signal so that a frequency of the beat signal is equal to that of the local signal.

Abstract: An apparatus and method of controlling the light intensity in a light source of variable emission affected by a drive signal. Spatial optical integration based upon light summation is incorporated into the accompanying encasement device at a backlight source by means of a light source support structure that allows light not directed toward a viewed surface, such as an LCD, to serve as a control input to the light drive signal.

Abstract: A method for determining when overall lamp intensity is stable for a lamp in a document scanner. The intensity of a relatively small portion of the lamp is controlled as part of a closed loop intensity control system. During a warm-up transient period, the intensity of the small portion of the lamp is monitored and power to the lamp is monitored. A changing power to the lamp indicates that the overall lamp intensity has not stabilized. Scanning is initiated when the intensity of the monitored portion of the lamp is within a predetermined control range and the power to the lamp has stabilized for a predetermined time period. The predetermined time period can be a default value or can be determined by a user.

Abstract: A detecting device can centrally monitor and detect a lamp failure of one or more lamps connected in series such as guide lamps in the runway of an airfield. A core (12) is disposed on a power line (P.sub.1) of each lamp (L.sub.1 -L.sub.n). The power line (P.sub.1) is wound on the core (12) as a first winding (N.sub.1). A second winding (N.sub.2) for extracting the power of the power line (P.sub.1) is wound on the core (12). An oscillator (13) is provided which uses the output voltage of the second winding (N.sub.2) as the power supply to generate a frequency corresponding to each lamp (L.sub.1 -L.sub.n). The output signal from this oscillator (13) is fed back to the power line (P.sub.1) through a third winding (N.sub.3). Accordingly, a signal consisting of a frequency which represents each lamp flows through the lamp circuit and any failed lamp or lamps can be detected by checking this feedback signal.

Abstract: Apparatus for controlling operation of a number of radiation generator assemblies comprises a store for storing calibration values for respective assemblies, respective switches, a digital to analogue converter (D/A) and control means. The switches are coupled between the radiation generator assemblies and D/A. The control means selectively addresses the store and controls the switches such that when a switch is closed a corresponding calibration value is supplied to the D/A to energize the generator assembly. Such apparatus is typically for use in monitoring of passage of sheets such as in banknote sorting.

Abstract: An image forming apparatus includes a detector for detecting light intensities of light from a light source, and a discrimination unit for obtaining the relative ratio of chroma signals of light with two or more wavelengths at the light intensities of the light source detected by the detector, to thereby discriminate life expiration of the light source. Data of the relative ratio of chroma signals of light with two or more wavelengths at a time of life expiration of the light source is obtained in advance. Thereafter, the light intensity of the light source is detected to obtain the actual relative ratio of the chroma signals of light with two or more wavelengths. Based on these data, the life expiration of the light source is discriminated.

Abstract: The invention relates to the idea of a device which can be interposed between a lamp and its socket for a variety of purposes including control of the operation of the lamp, hazard and security status detection. In one form the device is responsive to the light's wall switch being turned off and then rapidly on again to initiate a periodic energization of the lamp so as to give the impression that the room in which the lamp is located is occupied. Various other uses for the device are also disclosed.

Abstract: The present invention relates to an illuminated switch and in particular to one having a housing, switch contacts in the housing, an electrical device disposed in the housing and operatively associated with the switch contacts, a light transmissive colored filter mounted over a neon lamp of the electrical device, and a transparent member located over a cds photoresistor of the electrical device, whereby the neon lamp will light to provide indication of the switch location in darkness and will be extinguished when the switch is turned on.

Abstract: A light control apparatus for a vehicle is integrated with headlamp driving relays, a light sensor, a lighting switch which selects a manual mode or an automatic mode, and a control unit which controls the relays in accordance with the light sensor output when the lighting switch selects the automatic mode and turns on or off the headlamps. Two power source systems and two headlamp driving systems are provided. The signal level of a given terminal of the control unit is detected and is input to the microcomputer of the control unit. The microcomputer judges whether or not trouble has occurred by detecting a level difference. An alarm indication is given by a lamp or a buzzer if trouble is detected.

Abstract: A photosensor for detecting the light intensity of an external light source, usually the sun, which is illuminating an area is used as the sensor for a control network of an artificial lighting system for that same area to compensate for light intensity variations. The voltage output from the photosensor is applied to a logarithmic-to-linear device which is used as an input to a comparator for producing an inverse output that drives the artificial lighting system. The logarithmic-to-linear device inserts an element into the overall control system that provides compensation that corresponds to the perceived linear light change of intensity that actually occurs when there is an actual logarithmic light change.

Abstract: In order to provide a lamp failure warning in both illuminated and unilluminated states of the lamp, there is provided a resistance bridge circuit Rs, L, R2 and R3 which is substantially in balance if the lamp L is sound. An amplifier IC1 acts as a detection means if the bridge goes out of balance as a consequence of failure of the lamp L. In the unilluminated state a reduced current is fed to the bridge via a high value resistance R1, which is by-passed by a lamp switch SW1 if the lamp is to receive enough power to illuminate it.

Abstract: A box formed with an aperture in which a photosensitive cell is secured includes an electronic circuit connected to be fed by the electrical signal produced by the photosensitive cell when the latter is irradiated by ambient radiation. Said electronic circuit comprises a delay circuit adapted to receive the signal and arranged to produce a control signal when the cell has been irradiated for a predetermined time interval; an audible signal generator received in the box opposite apertures and connected to produce an audible signal in response to the control signal; and a circuit adapted to interrupt the audible signal after a predetermined time interval so that the audible signal is of predetermined duration.The box has means for securing it to an object which is required not to be lost accidentally, e.g. keys, a wallet, a diary, etc. A cover can be provided for being placed over the cell to protect it and keep away external radiations when the reminder device is not required to be operative.

Abstract: A protective device for a plurality of electrical circuits includes a pluity of isolated electrodes forming a gap with a common electrode. An output signal, electrically isolated from the circuits being monitored, is obtained by a photosensor viewing the discharge gap through an optical window. Radioactive stabilization of discharge characteristics is provided for slowly changing voltages and carbon tipped dynamic starters provide desirable discharge characteristics for rapidly varying voltages. A hydrogen permeation barrier is provided on external surfaces of the device.

Abstract: A self-contained photodetector for detecting the light flash from a photoflash unit which is supposed to flash when the shutter of a camera opens. The detector has a light-activated SCR for turning on an IC chip timer, which produces an output signal that turns on a transistor and causes a piezoelectric buzzer to produce an audible signal. All these components are powered by a battery which is contained in the same housing with them. This housing has an opening for passing light onto the SCR.

Abstract: A circuit for selectively lighting one of a pair of light-emitting diodes (LEDs) arranged in a parallel, back-to-back, circuit configuration also known as an anti-parallel circuit configuration. One side of the configuration is connected with ground connecting means through a first photon-emitting device which device is optically coupled to a first photon-responsive device connected between the other side of the configuration and a current source. The other side of the configuration is also connected with a ground connecting means through a second photon-emitting device which device is optically coupled to a second photon-responsive device connected between the first side of the configuration and the current source.

Abstract: In a pilot light usable for monitoring industrial control circuits a set of three terminals comprising a signal terminal, a test terminal and a line, or return terminal, with a signal circuit network between the signal and line terminals that supplies current to a lamp when a voltage is applied to the signal terminal, and with a test circuit network between the test and line terminals that supplies current to the lamp when a voltage is applied to the test terminal. Each circuit network includes a triac and a trigger branch subcircuit for controlling the associated triac.

Abstract: A pilot light as might be used for monitoring an industrial control circuit having a normal signal circuit connectable to a control circuit element for illuminating a lamp of the pilot light when such control circuit element is operated, and also having a test circuit connectable to a test switch for testing the integrity of the lamp when the test switch is operated. A circuit for supplying current to the lamp is light coupled to both the normal signal circuit and the test circuit.

Abstract: In the disclosed device, a sensor produces a corroborating signal when a computer flash unit emits a flash proper for an exposure. A timer energizes an indicator for a predetermined time in response to the corroborating signal. When the sensor produces a subsequent corroborating signal in response to another flash, while the indicator is energized, a reset device resets the timer. According to one embodiment of the invention, an overriding arrangement connected to the timer nullifies the operation of the timer a predetermined time after a flash emission.

Abstract: A flash device of the invention comprises, substantially, a flash unit for generating flash light and a flash control unit for controlling the flash light generated from said flash unit. The flash unit comprises electric power supplying means for supplying electric power, electric energy storing means for storing the electric energy supplied from said electric power supplying means, flash light generating means for converting the electrical energy stored in said electric energy storing means to an optical energy, and said flash control unit comprises, substantially, light receiving means for receiving a reflecting light, flash light quantity detecting means for detecting flash light quantity, means for indicating light exposure quantity, and flash light quantity control means. The flash device of the present invention is convenient to adjust the photographing distance and a diaphragm of a camera in photographing.

Abstract: A periodic current generator is connected with a long power supply line through a first transformer. The lamp of the traffic light is connected to the long line through a second transformer. First and second safety capacitors with four terminals each are respectively arranged in series on the long line with the first and second transformers. A DC current is generated by a detector when the lamp is operating. The detector is connected to one of the capacitors and the DC current passes through the long line to the second capacitor across which the coil of a relay is connected. The relay is actuated by the DC current and sends information concerning the status of the lamp to a central control station.

Abstract: A portable microwave leakage detector comprises a dipole antenna and a hot carrier diode connected in parallel with a light emitting diode, the circuit incorporating minimum solder joints and affording maximum sensitivity without moving parts such that the detector circuit does not decay with time. The dipole antenna is oriented diagonally in a detector case so that the user of the detector automatically presents the antenna to the radiating microwave field (or leakage field) at a maximum receiving attitude with respect to the field. The detector can be utilized to determine whether a microwave oven or any other device is leaking radiation beyond limits imposed by the Food and Drug Administration.

Abstract: An operation indicator for an automatic flashing device comprising a first indication means which visually indicates a reaching to a predetermined voltage of main capacitor and readiness for proper completion of flashing of an automatic light adjusting, and a second indication means which indicates a selected one of them by sound, and a switching means which connects or disconnects said second indication means to the circuit of the device.By the abovementioned construction, the user can realize readiness of automatic flash operation both by eyesight and by audition.

Abstract: A light activated control system, particularly for operating warning lights on a vehicle parked at night. The system includes a light sensor mounted on the vehicle and a comparator which triggers a time delay threshold device which switches on the warning lights for a predetermined period of about ten seconds only when the sensed light intensity increases through a threshold level due for example to the approach of a lighted vehicle. The system may alternatively be responsive to the rate of increase of sensed light level to switch on the warning lights.

Abstract: A plurality of photodetectors in a single line exposed to a field of view transversely across the complete region of a glow discharge volume. The detectors are connected in an electronic circuit to trigger a crowbar device across the power supply circuit providing the voltage producing the discharge when any one detector receives an optical input substantially greater than normal, thereby preventing damage to the discharge electrodes due to arcing across the glow discharge.

Abstract: An electronic flash apparatus is provided with a display element positioned in the view-finder of a photographic camera so that the operator is immediately aware if the flash tube has been fired in response to the closure of the synchronous switch. The light emitting operation of this display element is controlled by use of a signal generator arranged to be responsive to the occurrence of discharge through the flash tube of the flash apparatus. With this apparatus, therefore, the operator may rely upon the appearance of this display element to insure that the firing is effected by the flash apparatus even when the object-to-camera distance is relatively small.

Abstract: A neon tube flashing device having a neon tube which emits light upon application of a predetermined voltage thereto to effect indication of operational conditions comprises a capacitor parallel-connected to the neon tube, and switch means series-connected to the capacitor and parallel-connected to the neon tube. The neon tube may be caused to effect flashing by charging-discharging of the capacitor during conduction of the switch means.

Abstract: An electronic flash unit for photographic purposes, with improved means for quenching the flash when sufficient light has been emitted from the flash tube. The discharge circuit of the main storage capacitor comprises the flash tube and a switch thyristor in series with each other. A quench circuit including a quenching capacitor and a quenching thyristor will deliver a quenching current to the switch thyristor when the quenching thyristor is triggered by exposure metering and flash limiting mechanism, this mechanism including a resistor, a phototransistor, and an integrating capacitor in series with each other and in parallel with a feed capacitor which supplies feed current to the exposure metering and flash limiting mechanism, and which is in parallel with the switch thyristor.

Abstract: An optoelectronic device comprising a light-sensitive device which produces or modifies an electric current in dependence upon the intensity of light incident thereon, and a light-emitting device arranged to emit light in response to said electric current and so disposed that part of said emitted light is incident upon the light-sensitive device to provide positive feedback.

Abstract: An electronic flash unit having the conventional flash tube, storage capacitor dischargeable through the flash tube, measuring device for recording the quantity of light emitted by the flash tube and reflected back from the subject being photographed, a pulse generator responsive to the measured reflected light, and means for quenching the flash in response to a pulse produced when the measured reflected light reaches a threshold value. The present flash unit, in addition to the conventional features just mentioned, includes the novel feature of a light-emitting diode which becomes illuminated when the light measuring means and the pulse generator circuit become operative, thus signalling to the user of the device that the so-called "computer" mechanism has actually operated. Circuit means is provided for extinguishing the light-emitting diode at the proper time.

Abstract: An electronic flash apparatus includes a correct exposure annunciator which operates if light received from the subject exceeds a predetermined percentage of the required illumination.

Abstract: A correct exposure annunciator for electronic flash apparatus includes an indicator which is turned on when the voltage on a capacitor is less than a predetermined value. The capacitor is discharged in response to a control signal which indicates that proper exposure has occurred. The capacitor is then recharged until the voltage on the capacitor attains the predetermined value and turns off the indicator.

Abstract: This invention relates to a light-measuring apparatus wherein a photoelectric element is arranged in a leg of a measuring bridge, the output voltage of said element controlling the brightness of two signal lamps.

Abstract: An electronic flash apparatus terminates the light flash when light received from the subject has reached a predetermined level. The light terminating means includes a terminating capacitor which is discharged during the termination of the flash. Annunciator control signal generating means senses when the terminating capacitor is being recharged, and produces an annunciator control signal. An annunciator receives the annunciator control signal and provides an indication that the light terminating means has terminated the flash.