Abstract: A filament lamp outage indicator system in which the actuation of an on/off switch to its on position is sensed to enable a logic circuit in the event a current flow increase is not inductively detected in a conductor in series with the switch and a corresponding filament lamp.

Abstract: In a motor vehicle comprising headlights, an ignition switch, and an electric energy storage battery, there is provided a device for automatically turning on and off the headlights. A first and a second comparators responsive to two different reference voltages and to the voltage V present between the terminals of the battery determine whether the voltage V has an amplitude located within a predetermined range of voltage amplitudes. An electronic switch interposed between the battery and the headlights is controlled by the outputs of the first and second comparators to turn the headlights on when the amplitude of the voltage V is located within the predetermined range, and to turn the headlights off when the voltage V is outside of this range. The device is connected to the battery so that it operates only when the ignition switch is closed. The device is also connected in parallel with the normal, manually operated lighting switch so as to allow normal operation of the headlights through the latter switch.

Abstract: A microprocessor circuit employed to control the on/off switching of a filament lamp in series with a power switching device and a single conductor is programmed to periodically cycle the filament lamp between its deenergized and energized state at a rate above that which would be humanly perceptible. A toroidal ferrite core surrounds the conductor between the lamp filament and the switch and picks up current changes which occur due to the cycling. The absence of current changes during cycling are perceived by the microprocessor as a lamp failure and appropriate signaling is made to indicate the lamp failure.

Abstract: A marker light using an array (2) of light emitting diodes (12) in combination with lenses (3) provides a light beam of required intensity, shape and color for railroad applications. The light emitting diodes are arranged in various configurations to form the array (2). The lenses may be Fresnel lenses. Control circuitry (C) energizes the light emitting diodes at predetermined or variable flashing rates. Sensing circuitry (222) senses the failure of light emitting diodes in the array and provides an indication of such failure.

Abstract: An electric element breakdown detector includes an electric element (5: 5a: 106: 132: 172) connected in series with a switching element (6: 6a: 116: 116a: 171) which define a series connection. A processing circuit (40: 110: 174) produces a control signal to the switching element to control on and off operation of the switching element, so as to control the current flow through the series connection. A comparator (10: 119) is provided for comparing a voltage at one end of the electric element with a reference voltage produced from a reference voltage producer (12: 121, 123), and generates a result signal representing the result of the comparison. The result signal is fed to the processing circuit. The processing circuit detects the condition of the series connection by the detection of combination of the control signal and the result signal.

Abstract: A combined magnetic and thermal activated relay for use in alarm systems. The relay includes a thermal activated bimetal switch in series with the current through the magnetic coil which activates a magnetic switch. The thermal switch is in a normally closed state and the magnetic switch is in a normally open state. When current passes through the coil the magnetic switch changes from its normally open to a closed state applying voltage potential for an external requirement. The heat generated by the coil's resistance to current flow heats the core of the magnetic coil, and after reaching an elevated temperature level the thermal activated switch changes from its normally closed state to an open state opening the current flow path through the magnetic coil causing the magnetic switch to return to its normal open state removing voltage for the external requirement. The switching operation of the thermal switch cycles with temperature changes.

Abstract: A microcomputer controlled monitoring system and method for detecting an electrical open, shorted or operative condition of an electrical load. A load switch circuit couples the load to a common voltage line and is controlled by a single drive line from a microcomputer controlled load monitor circuit.

Abstract: A lamp monitor for detecting the failure of headlamps and other lamps on an automotive vehicle includes a failure detection circuit coupled to the lamp circuit to produce an output whenever the lamp circuit is operating and a failure occurs. A latch circuit responsive to the detector output and powered from the vehicle battery latches into a failure state when a lamp failure is detected and maintains that state even though the lamp circuit or the vehicle ignition circuit is switched off. The latch output triggers an indicator circuit to reveal an indication or warning when the vehicle ignition switch is turned on even though the lamp circuit is turned off and the ignition switch has been opened subsequent to the detected failure. Upon correction of the failure, the detector resets the latch circuit when the lamp circuit is actuated to disable the display.

Abstract: A memory device for lighting control purposes, including, for example a battery. The charge of which is controlled by at least one photodetector, which receives light from a lighting means when the latter is in operation. Charging the battery takes place during an operating period of the lighting means. When the latter is not operating, the battery discharges into a light emitting diode. Thus, the information concerning the satisfactory operation of the lighting means is stored for a certain time and after said operation it is possible to check that the latter has taken place. The device has applicability to the control of a public lighting system.

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: A test circuit is disclosed for testing the continuity of a load circuit, such as a vehicle lamp circuit, and indicating a discontinuity when the load circuit is either energized or de-energized. The test circuit comprises an indicating circuit with an LED and a switching transistor in series and a voltage divider for biasing the transistor to a conductive state. The detecting circuit includes a reed switch which is closed in response to load current for connecting a point on the voltage divider to ground to switch the transistor off. The detecting circuit also includes current blocking means such as a diode for connecting the voltage divider to ground through the load circuit so that the transistor is switched off when there is continuity in the load circuit to ground.

Abstract: A signalling apparatus has at least one transmitter in a transmitter assembly for transmitting a signal by impressed current to several spatially separated receivers. A series circuit of threshold members is connected to the output terminals of each transmitter, the number of members corresponding to the number of receivers. The input of each receiver is connected to a threshold member; the receivers are therefore connected in series on the input side. It is ensured thereby that the same current flows through all receivers. In the event of a failure of a transmission line or a receiver, the current continues to flow through the associated threshold member so that signal transmission to the other receivers continues uninterrupted.

Abstract: To provide an indication of the presence of a trailer connected to a vehicle, operating as a tractor, without any additional terminal or contact elements on a plug-socket connector between the electrical system of the tractor and the trailer connected thereto, a logic gate (11), preferably a NAND-element, is connected to the output line of the direction flasher circuit, or other suitable connecting line, to a low-resistance load on the trailer, for example the brake light (19a), position lights or the like, the resistance circuit element including a connection from the positive power supply through a resistor (12) having a value which is high with respect to that of the lamps on the trailer (19, 19a) so that, with the trailer disconnected, an effectively 1-signal will be applied to the logic circuit but, upon connection of a low-resistance lamp, that is, upon connection of a trailer socket, the signal at the logic gate will drop to a O-signal although the current through the lamp is insufficient to cause ligh

Abstract: In the disclosed display, the symbol segments of a passive cell, such as a liquid crystal cell, are each connected to one of two leads through an elastic connector layer having mutually insulated conductors running through the layer transverse thereto. According to an embodiment of the invention, the leads are on a printed circuit board and a control bus connects one of the leads to a control unit that operates the cell and a second bus connects the other of each of the leads to a monitor unit that compares the potential at each segment with the potential at the control unit. This checks the connections between the control unit and each segment.

Abstract: A stop-light monitor device includes a source of current, a lighting circuit connected with the source and having a stop-light switch actuated by the brake pedal. The lighting circuit has incandescent lamps which are energized when the brake pedal is depressed. A magnetic reed switch is influenced to closed position by a permanent magnet, and is connected to control a solid-state switch which in turn controls a pilot light that becomes illuminated when the solid-state switch is closed in consequence of the reed switch being opened. A current-sensitive coil connected with the lighting circuit, opens the reed switch in response to normal energization of the stop lights, whereby the pilot lamp is energized. If a stop light burns out, the reed switch closes, opening the solid-state switch whereby the pilot light is extinguished, giving an indication of the malfunction.

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 fail safe type of monitoring circuit for contacts is provided using an opto-isolator. The opto-isolator is energized in response to the operation of the contacts to clearly indicate whether the contacts are open or closed, and whether the circuit components are functioning in a valid manner.

Abstract: A direction indicator system for a road vehicle includes a selector switch operable to select the operation of one or the other set of direction indicator lamps of the vehicle, the selector switch being connected in series with a pair of relay contacts. An oscillator is provided for driving the relay the oscillator including a capacitor having a charge/discharge circuit and switch means having a control input. A reference voltage source is provided including switch means also having a control input. The system includes a comparator for comparing the capacitor voltage and reference voltage the comparator providing a signal to control the relay when the voltages are substantially equal.

Abstract: A device for indicating when one or more fluorescent lamps in a bank of fluorescent lamps burns out requiring only a single indicator is disclosed. The device includes a voltage divider connected to a terminal of each lamp to produce a signal proportional to the voltage supplied by a ballast to the terminal of the lamp. These signals are then summed at a common summing terminal. The voltage at the summing terminal is approximately equal to the largest voltage of the individual signals produced at each lamp. The signal at the summing terminal is modified, typically through an adjustable voltage divider, to produce a third signalwhich is applied to the gate of an SCR. The adjustable voltage divider is designed so that when any one of the lamps goes out producing a substantial rise in the voltage applied by the ballast to the lamp, the SCR will be triggered. An indicator bulb is connected to the anode of the SCR so that when the SCR triggers, the bulb lights indicating one or more of the lamps are burned out.

Abstract: A low liquid level electro-optical probe is made self-checking by providing the same with means for intercepting a portion of the usual light beam and constantly reflecting such portion to the usual receiving electro-optical transducer to constantly generate a low level electrical signal even when the probe is wet. Means are provided for boosting the signal to activate an alarm, failure of which will be indicative of failure or malfunctioning of one or more elements of the system.

Abstract: A control circuit for the turn-signal flasher system of an automotive vehicle. The flasher system includes a relay having switch contacts which are serially connected, together with a direction indicator switch, between the vehicle battery and the turn-signal lamps. A measuring or sampling resistor is connected between the battery and the relay contacts. First and second pulse generators are connected between a first voltage indicator and the relay coil, and are selectively gated to interrupt the relay during normal lamp load conditions. The first pulse generator provides a normal mark-to-space ratio whereas the second pulse generator provides a reduced mark-to-space ratio for use during night driving conditions. Third and fourth pulse generators are responsive to corresponding voltage indicators connected to the measuring resistor. The third and fourth generators function to respectively provide different mark-to-space ratios in response to, and indicative of, lamp outage or current-overload conditions.

Abstract: The installation includes a main load supplied with power by an a.c. source such as a magnetic flywheel of a moped and a current detector connected in series in the supply circuit of the main load. This detector provides, as a function of the current detected for, the automatic supply of power to a system for monitoring the operation of the main load or of a secondary load also supplied with power by the source.

Abstract: The invention relates to a fault detector for light bulbs. It comprises an inductance connected in series between the bulb and a control switch, the arrangement being supplied with direct current. An alarm device, connected to the junction point between the bulb and inductance, is polarized in order to trip the alarm when the control switch is closed unless prevented from so doing by a tripping control circuit. The tripping control circuit responds to current flowing to the bulb subsequent to the closure of the control switch to prevent the actuation of the alarm device throughout the period of closure of the control switch.

Abstract: A circuit is described here for liquid crystal indication systems made up of segments which, using the capacitive performance of the indication system, automatically reveals errors that arise in the segments or due to short-circuits between segments.The invention is adapted for use especially in scales that are to be guaranteed against functional errors.

Abstract: A circuit for detecting failure of a segment in a digital display which includes a comparator connected to the energizing circuit for the display segments so that when a segment fails and is addressed, the comparator output is changed to provide a blanking signal which is fed by a circuit to the blanking input of the display driver for blanking the display. The energizing circuit for the display includes lamp test means, which, after display blanking, is actuated to energize all of the segments thereby permitting identification of the failed segment. Release of the lamp test means activates a timer circuit for providing an override signal for overriding the blanking signal to return the display to normal operation for a predetermined period of time following which the display will be blanked again when the failed segment is again addressed.

Abstract: A monitoring circuit for electrically conductive resistive devices such as diesel glow plugs in which the devices are fed through an electrically sensitive path, and the voltage across the electrical devices is sensed with respect to a reference. If the sensed voltage is above the reference indicating the presence of a defective device, a warning is indicated. The circuit includes means allowing warm up of the devices before sensing, and for inhibiting signals, which would otherwise indicate a false warning, after a chosen period for sensing.

Abstract: A flasher apparatus for vehicles capable of informing the presence of short-circuit in a direction indicating system and protecting the direction indicating system from burnout. The flasher apparatus receives both a flashing signal for energizing direction indicating lamps and a detection signal indicative of the electric current flowing to said direction indicating lamps. The detection signal is compared with a reference signal so that the short-circuit in the system is detected. Upon detection of the short-circuit, the direction indicating lamps are prevented from being energized to thereby inform the presence of short-circuit and protect the system. The short-circuit detecting operation is disabled for a period of time in which a comparatively large rush current flows to the direction indicating lamps.

Abstract: One electrode each of at least selected ones of the segments of a seven segment liquid crystal indicator is connected to a test lead as well as an energizing lead. The voltage level of the energizing lead is compared to that of the test lead and an error signal is furnished if there is no correspondence therebetween. Where the seven segment indicator has a plurality of digits energized by a multiplexer, the electrodes of corresponding ones of the segments in each digit can be connected together and only one test lead is then provided for the so-formed set of segments.

Abstract: An improved apparatus for use in the turn-direction indicating system of a vehicle having at least front and rear directional lamps. The directional lamps are connected in parallel with each other to be energized by a battery through a current detecting resistor, a relay and a direction selecting switch. The relay is energized to close periodically in response to periodic pulse so that the directional lamps flash periodically. Generation of the periodic pulses is controlled in response to the voltages appeared across the current detecting resistor and at the junction between the relay and the direction indicating switch. The relay is adapted to function as an alarm buzzer for informing the disconnection of both front and rear directional lamps.

Abstract: A battery monitoring circuit for an electronic wristwatch that avoids an inadvertent indication of battery failure when a sudden, but temporary, load is placed upon the battery is provided. The invention is characterized by a monitoring circuit that produces an indication signal of impending failure of the battery in response to a detection signal being applied thereto. The detection signal is produced by a battery detection circuit when the voltage of the battery falls below a predetermined level. An inhibit circuit is coupled intermediate the voltage detection circuit and the monitoring circuit and detects when a temporary load is placed upon the battery and, in response thereto, inhibits the detection signal from being applied to the monitoring circuit to thereby prevent an indication signal, representative of imminent battery failure, from being produced as a result of an additional load being temporarily placed upon the battery.

Abstract: A lamp failure detection arrangement includes a device for interrupting electrical energy to a lamp, and a testing device for generating a low level test signal and for supplying it during the testing interval to the lamp for test purposes without causing the lamp to provide illumination. A device responds to the test signal indicating a failure condition of the lamp for generating a failure condition signal, which can be used both to energize a standby lamp and to generate an attention-attracting signal for alerting an attendant to replace the faulty lamp.

Abstract: A driver circuit for an electrical load device such as an indicator lamp includes the capability to both drive the lamp and to respond to a fault condition in the lamp to disable its energization. The circuit is adapted for control by a single I/O terminal of a programmable logic device. The I/O terminal being of the type having an internal architecture that causes the terminal to be pulled up to a logic high state when unloaded, and pulled down to a logic low state by either external loading or the closure of an internal; program-controlled switch forming part of a low-impedence path to ground. A processor-implemented test routine can be used to monitor the I/O terminal voltage and close the internal switch when the driver circuit responds to a shorted condition.

Abstract: A lamp outage indicator circuit for sensing and indicating outage of remotely located lamps in a vehicle. The lamp outage indicator employs a semiconductor sensing device to sense the voltage excursion which occurs when a lamp burns out. The sensing semiconductor is located in a bridge circuit to negate the effects of voltage and temperature fluctuations on the operating point of the circuit. Further, the sensing semiconductor device is located in the circuit so that in the normal operating state, a reference semiconductor device is on while the sensing semiconductor device is off. Lamp outage causes the current to shift from the reference semiconductor device to the sensing semiconductor device so as to turn the reference device off, and the sensing device on to energize an appropriate indicator. In one embodiment, the sensing semiconductor device is a light emitting diode while in a second embodiment, the sensing semiconductor device is a transistor.

Abstract: A pulse generator comprises a comparator to the inputs of which are connected a capacitor chargeable by a power source and a voltage divider respectively, two transistors being connected to the output of the comparator, one to set the voltage ratio of the voltage divider and one to provide a discharge path for the capacitor and two additional transistors being selectively connected to the comparator output, one providing a different voltage ratio of the voltage divider and the other providing an independent discharge path for the capacitor.