Abstract: A device for protection against power failures, having a programmable current source with two levels, which are controlled by a threshold detector, the current from the source being large at high voltages and reduced at low voltages.

Abstract: A circuit for sensing a plurality of inputs, each of which have a plurality of condition states, and providing a visibly coded output signal to a single indicator lamp, or the like, whereby one may readily determine the various condition states. The circuit is exemplified in an automotive voltage and current sensing system which senses the conditions of normal voltage, overvoltage, undervoltage and battery discharge. The circuit commands a single lamp to be off, to flash rapidly, to light continuously, or to flash slowly in correspondence to the particular sensed condition.

Abstract: A portable cooler includes a urethane foam shell having a storage compartment and fan recess. An internal heat exchanger is mounted to a wall of the storage compartment and conducts heat out of the storage compartment by means of a thermally conductive block to an external heat exchanger mounted in the fan recess. An electric fan mounted in the fan recess blows outside air through fins of the external heat exchanger. A grill covers the fan recess. A solid state thermoelectric device is disposed between the external heat exchanger and the thermally conductive block. A control circuit includes a first thermistor which senses the temperature of the internal heat exchanger. A comparator having one input coupled to a temperature control reostat and another input coupled to the first thermistor controls a switch circuit which connects the terminals of the thermoelectric device and the terminals of the fan motor to a supply voltage conductor.

Abstract: An MOS low voltage detector circuit includes a comparator which compares an internally generated reference voltage with an internally generated non-linear voltage. Both the reference voltage and the non-linear voltage are derived from a supply voltage, and the comparator generates an output whenever the divided down non-linear voltage falls below the reference voltage. This output is supplied to a series of regularly biased MOS inverter stages which not only amplify the comparator output but also amplify the inherent offset error in the comparator itself. Voltage compensating means may also be included in the comparator.

Abstract: The pedestrian traffic control system of this invention utilizes an endless belt to successively display visible painted WALK, DONT START, and DONT WALK signs in a window of a display unit. The control unit may be employed with an ordinary three-state power system of the type that now operates flashing neon signs, but has the advantage that electric power operates the signs only when a sign is being moved into display position. Three distinct WALK, DONT START, and DONT WALK signs are used thereby avoiding the ambiguity of present systems in which a flashing DONT WALK sign cautions the pedestrian not to start, but to continue on his way. The movement of the endless belt is controlled by detecting markers, such as perforations, on the endless belt, thus assuring proper registration of the signs in display position. Electrical energy that becomes stored while the sign is energized drives the sign to display the DONT WALK sign, if the power fails.

Abstract: A home safety unit having an emergency light system for providing light in the event of a power failure or the detection of a fire condition, and a fire detection system for providing an alarm indicating the existence of a fire. The safety unit is designed to have an aesthetically pleasing appearance and to be installed inconspicuously between the base of an existing light fixture and a wall or ceiling. Installation of the safety unit is a simple process, whether installing it when constructing a new building or by retro-fitting it into an existing building.A modified light switch having parallel impedance across the light switch terminals is installed to provide continuous power to the safety unit when the switch is in its off position. Also included is a low voltage dropout system for disconnecting the auxiliary lights when the battery voltage falls below a certain level and for providing an audible alarm indicating this low voltage condition.

Abstract: An alarm circuit indicating a defect in a car alternator, said circuit comprising a voltage divider formed by two resistors connected between the positive terminal B+ and a negative terminal D- of the alternator, the center point of the voltage divider being connected to the control electrode of a commutation circuit of which the output path is serially connected with a lamp between the terminals of the battery, and rectifier means being provided for preventing the battery to discharge through the voltage divider.

Abstract: A power line disturbance (PLD) detector circuit includes a digital counter which is driven by pulses provided by a clock in an associated data processing system. The PLD detector circuit includes a comparator amplifier for comparing primary AC power to a DC reference voltage on a cycle-by-cycle basis. The amplifier generates a reset pulse once during each AC cycle as long as the AC voltage exceeds the DC reference voltage. When a decoder circuit detects a count outside the range of counts attained by the digital counter between normally occurring reset pulses, the decoder circuit responds by generating a PLD signal. The PLD signal is provided both to the associated data processing system and to a Power On Reset circuit. The Power On Reset circuit is initialized by the PLD signal, permitting the circuit to respond consistently upon subsequent restoration of power.

Abstract: A method and apparatus for controlling the various functions of an internal combustion engine using a program-controlled microprocessor having a memory preprogrammed with various control laws and associated control schedules receives information concerning one or more engine-operating parameters such as manifold pressure, throttle position, engine coolant temperature, air temperature, engine speed or period and the like. These parameters are sensed and then supplied to input circuits for signal conditioning and conversion into digital words usable by the microprocessor. The microprocessor system computes a digital word indicative of a computer-commanded engine control operation and output circuitry responds to predetermined computer-generated commands and to the computed digital command words for converting them to corresponding pulse-width control signals for controlling such engine operations as fuel-injection, ignition timing, proportional and/or on-off EGR control, and the like.

Abstract: A three phase undervoltage monitor separately converts the voltage on each phase to a D.C. voltage, compares each of the separate D.C. voltages with a reference voltage, and operates an output signal whenever one or more of the voltages drops below the reference voltage.

Abstract: Audible or visual warning signals are employed in a pump system having a primary and an auxiliary pump to indicate loss of power or a malfunctioning pump. Float switches react to a rising liquid level, thereby opening fail-safe circuits, and closing warning circuits which give sensory perceptible signals.

Abstract: The sensor system senses a drop in the flow of impressed cathodic protection current to a minimum threshold level. A potential difference is developed which is a sample of the cathodic protection current. A comparator receives the sample potential difference and normally produces an output control signal which drops to substantially zero when the cathodic protection current drops to a predetermined threshold level. A relay responsive to the control signal then switches a signaling device to its signaling condition. A standby battery is also coupled to the signaling device through the relay. In the event of any failure in the sensor system or in the primary source of power energizing the sensor system, the standby battery becomes connected to the signaling device to cause it to change to its signaling condition.

Abstract: In an electronic timepiece having a stepping motor, a drive pulse is produced for normally driving the motor, a detecting pulse is generated for detecting whether the motor has rotated in response to the last drive pulse and a correction pulse is produced for driving the motor when non-rotation has been detected. A current limiting resistor is disposed in series with the motor for limiting the current thereto and a switching transistor is connected across the current limiting resistor to short circuit same to effect an increase in the current to the motor. During the detecting pulse, the voltage across the current limiting resistor is compared to a predetermined value.

Abstract: An alarm circuit to monitor a periodic signal source for an occurrence of a short-circuit condition detects the entry of the instantaneous periodic signal magnitude into a predefined window bounded by an upper and lower threshold. The duration of the entry is timed to determine if a short circuit has occurred.

Abstract: A phase unbalance detecting system that includes also low-voltage detection and wrong-phase-sequence detection. The system can be packaged in a small volume because it is a solid state type that uses a minimum of electronics and does not require transformers for obtaining signals from the several phases of the plural-phase power line but only one transformer for the D.C. power supply circuit for the detection system. The system incorporates means for allowing it to be used at 50 or 60 Hz without separate adjustment, for making it insensitive to noise and harmonics of the power line, and for providing a good estimate of the negative sequence voltage caused by a phase unbalance. It provides external terminals whereby it can be adapted for use at different power line voltages.

Abstract: The voltage that occurs across the run capacitor of a permanently split capacitor type motor when the motor is in operation is quite high compared to the voltage that is present if the motor is stalled. These different voltage conditions are sensed through the use of a voltage pickoff to control an optical type isolation circuit which in turn controls a switch means to energize a fault indicator.

Abstract: An abnormal voltage detection circuit includes a series circuit of a resistor and a capacitor coupled across a power source by means of a switch, an inverter with the input terminal coupled to the junction of the resistor and capacitor, and an R-S flip-flop circuit with the set and reset input terminals coupled to the output terminal of the inverter and a manual switch respectively. The R-S flip-flop circuit is set by a first threshold voltage lower than the threshold voltage of the inverter, and reset by a second threshold voltage higher than the threshold voltage of the inverter.

Abstract: A circuit for detecting battery voltage for example in an electronic watch in order to provide a warning that the battery is almost depleted comprises two NOT circuits connected across the battery terminals. Each of the NOT circuits comprises a P-channel MOS transistor and an N-channel MOS transistor. The output of the first NOT circuit is connected to the input of the second NOT circuit and also through a biasing resistance to the input of the first NOT circuit. The output of the second NOT circuit is connected to circuitry for presenting a visual display when the output is inverted. When the voltage of the battery drops below a predetermined level, the output of the second NOT circuit is inverted to provide an indication that the battery is nearing depletion.

Abstract: An electro-mechanical transducer driver circuit for an electronic timepiece characterized in that the pulse width of a driving pulse which drives an electro-mechanical transducer is controlled in a step-wise manner by the induced voltage of a driving coil.

Abstract: A delay circuit includes a switching element for operatively switching between a first position and a second position. The switching element connects an input voltage to an electrically-operated device in the first position. A delay element is operatively connected to the switching element for maintaining the switching element in the first position when an input voltage interruption occurs which is less than a pre-determined time interval.

Abstract: An audible warning device is integrated within an electrical connector in the form of a mains plug or mains adaptor to produce an audible warning in the absence of the mains supply. The plug or adaptor may incorporate further circuits for producing distinctive warnings should the power supply be subsequently reconnected, and also should the voltage of an internal battery powering the device drop below a predetermined value. In the case of an adaptor, the device has such internal connections that a warning will be produced if the power supply plug becomes disconnected from the adaptor, the adaptor from the power supply socket, or both.

Abstract: An alarm bell especially adapted to be used in combination with a system which simultaneously detects smoke, fire, current failure, and unauthorized entry into an enclosure. The alarm bell has a housing which suports a bell dome. A mechanical motor is contained within the housing and is connected to actuate a first clapper which strikes the dome and sounds an alarm. A second clapper is actuated by an electric motor and is also placed adjacent to the dome. The first clapper cooperates with an electro-magnet such that the magnetic attraction therebetween prevents movement of the first clapper when the electro-magnet is energized. Accordingly, the electro-magnet can be connected to the same source of current which is used to energize the second clapper so that should the source of current fail, the electromagnet will release the first clapper thereby causing the mechanical motor to sound the alarm.

Abstract: Apparatus for supervising the energy level of a battery is characterized by circuitry for periodically loading the battery, monitoring the change in voltage across the battery from the condition prior to loading to during loading, and generating a signal whenever the change in voltage is at least equal to a predetermined magnitude. In one embodiment the apparatus is used with a fire detector powered by the battery, and the signal operates an alarm to indicate impending battery failure.

Abstract: A circuit for protecting electrical apparatus from undervoltage of a source voltage by providing disconnection of the apparatus from the same. The circuit includes a relay controlled by a transistorized portion of the circuit responsive to conduction of a gas-discharge tube having specific breakdown and extinguishing voltage characteristics. The tube senses a voltage of that portion of the circuit having selectively adjustable A.C. and D.C. components proportionate to the source voltage, wherein a plurality of source voltage differentials can be selectively chosen at which connection and disconnection of the apparatus will be effected. The relay is also coupled to a capacitor to provide a time delay to prevent relay operation upon momentary voltage fluctuations.

Abstract: In a timekeeping arrangement, including seconds, minutes and hours counters and associated display decoding circuitry, during temporary power line dropouts, the supply voltage for the hours and minutes counters is maintained by an associated voltage storage capacitor so that their contents are retained, and, upon the return of line power, the seconds counter is set to a number corresponding to 30 seconds. In this manner, over a number of random temporary power dropouts, the accuracy of the timekeeping arrangement is maintained without the need of readjustment or the use of auxiliary systems powered by standby power sources.

Abstract: A power supply interruption detecting circuit which prevents an error in a write signal or sending and receiving signals of a data processing unit in the case of interruption of a commercial power supply or a power supply voltage drop resulting from an accident of other units connected to the same power supply. An abrupt drop of the power supply input voltage is detected by comparing the voltage of a CR circuit of a small time constant with the voltage of a CR circuit of a relatively large time constant. A slow input voltage drop is detected by comparing the voltage of the CR circuit of small time constant with a constant reference voltage. The power supply interruption is rapidly detected in substantially a constant short time regardless of input voltage variations and the write signal or the sending and receiving signals are each clamped at predetermined logic voltage, by which sending and writing of an error signal can be effectively prevented.

Abstract: Time pulse generator having biasing means therefor including a control device, which may be a transistor and means interconnecting the biasing means to the battery being monitored. The output of the time pulse generator is utilized to drive a signaling device to indicate a low level of battery energy and/or an alarm condition as detected by an external condition sensor.