Abstract: A temperature sensing system for a switching device is provided The temperature sensing system includes a sensing device that is configured to sense a temperature of the switching device and a signal converter that is configured to output a digital signal having a frequency based on a voltage across the sensing device by a frequency variable method which receives the voltage across the sensing device which is a temperature sensing value when a current flows in the sensing device to convert a level of an analog signal into a frequency of the digital signal. An isolator is configured to be connected to an output terminal of the signal converter to isolate and transmit the digital signal output from the signal converter. The system also includes a controller configured to recognize the temperature from the frequency of the digital signal transmitted through the isolator.

Abstract: An information handling system includes a power source configured to provide a plurality of power levels to a load. At least one of the plurality of power levels corresponds to a level obtained by de-rating a capacity of the power source from a nominal design specification of the power source.

Abstract: A voltage compensation system for an A.C. power line supplying one or more air conditioners, a telephone system or other telecommunication system, a battery charger, or some other utilization system that should have an input voltage within a given normal range. The voltage compensation system includes a transformer unit containing a transformer having at least two windings coupled electromagnetically by a transformer core; one of those windings preferably is in two segments that are connectable in series or in parallel. One winding is connected to an input terminal and to an output terminal. The other winding adds to the A.C. line voltage when the line voltage drops below a low voltage threshold and/or subtracts from the line voltage when the A.C. line voltage exceeds a high voltage threshold. If the A.C. line voltage is in the range required by the utilization system, the other transformer winding is effectively shorted out or otherwise disconnected.

Abstract: A voltage compensation device for a two-conductor A.C. power line supplying one or more air conditioners, a telephone system or other telecommunication system, or some other utilization system that requires an input voltage within a given range. The device includes a transformer having electromagnetically coupled primary and secondary windings with the primary and secondary each connected to at least one output terminal. One winding is connected to add voltage to the A.C. line voltage when the line voltage drops below a given low voltage threshold, and in bucking (subtractive) relation when the A.C. line voltage exceeds a given high voltage threshold. When the A.C. line voltage is in the range required by the utilization system, the one winding is effectively shorted out or otherwise disconnected. A sensor for the line voltage actuates one or more relays connected to the transformer to effect the desired compensation action.

Abstract: A monitoring system for an electrical power control system having a plurality of electrical components operable in electrically conductive and non-conductive states in response to command signals from a system controller. The controller is connected for receiving status signals indicative of the conductive and non-conductive states of selected ones of the electrical components. The monitoring system develops variable frequency electrical signals representative of preselected conditions of preselected ones of the electrical components, combines the variable frequency electrical signals with the status signals, and transmits the combined signals to the system controller. The system controller extracts the variable frequency electrical signals from the combined signals for determining the state of the preselected conditions.

Abstract: A control system is provided for controlling the average power from an alternating voltage source (AC) to a load having inductive properties. The system uses a synchronous switch shunted by a capacitor connected between the source (generator) and sink (load) to pulse duration modulate the AC voltage carrier wave. A control signal generator circuit drives the synchronous switch such that the switch is closed at a variable time early in each half-wave of the AC voltage source carrier wave and such that the switch is opened at a subsequent later, variable time during that half-wave. This is accomplished by sensing the voltage across the synchronous switch in order to inhibit closing of the switch early in the half-wave until the synchronous switch voltage (and thus the voltage on the capacitor) is substantially zero and then opening the synchronous switch at a point in time to give the desired volt-second area between closure and opening within each half-wave.

Abstract: A touch control circuit is disclosed, which delivers power at any one of a plurality of different levels. To accomplish this, a line cycle delay timer provides a plurality of output signals, each signal being spaced apart in time from the line voltage zero crossing time and from each other. Power level memory and gating means gate the timer output signals to the power delivery means so as to trigger the power delivery means at any one of a number of different levels. A touch detector is connected to the power level memory means. Touch detector circuitry alters the power level memory so as to correspondingly alter the power delivered by the power delivery means when the touch detector is touched.

Abstract: The temperature of the power semiconductor component is sensed by a bipolar transistor. The bipolar transistor is in series with a depletion mode MOSFET whose gate and source electrodes are connected together. The drain electrode is also connected to a threshold element. Normally, the FET has low impedance, so that at the input of the threshold element source potential, e.g. ground potential, is present. With current rising as a function of temperature, the current through the FET is limited to a constant, essentially temperature-independent value, and the potential at the input of the threshold element rises steeply. This condition is detected as an overtemperature signal.

Abstract: A two-terminal A.C. device is described which can be series connected with a lighting fixture to prevent overheating of the fixture in an overload condition, namely, when a lighting element exceeding the power rating of the fixture is installed. In broad terms, the device includes a bidirectional, self-extinguishing switch which can be triggered to conduct current between the two terminals of the device, and control circuitry operable from the voltage difference and current between the two terminals occurring in use to regulate the triggering of the switch. The control circuitry includes triggering circuitry which generates triggering signals from the voltage difference across the terminals of the device and normally applies the triggering signals to the control terminal to permit a predetermined measure of conduction.

Abstract: A relay switch in an ac main line has a dc-powered applying for applying amplified control sensor signals to the control circuit of the relay switch. To provide dc power for the amplifier when the relay switch main controlled current conduction path is conductive, a current transformer primary winding is arranged in series with that path, and the voltage appearing across the secondary winding is rectified. To provide dc power for the amplifier when the relay switch main controlled current conduction path is non-conductive, an open-circuit voltage related to that appearing across the open-circuit non-conductive path is rectified. To permit the use of one rectifier for developing dc power for the amplifier it is advantageous to apply the open-circuit voltage to the secondary winding of the current transformer through a dc-blocking capacitor with sufficient ac impedance to restrict ac flow across the open-circuit relay switch path.

Abstract: A temperature-responsive circuit, for operation with a load-control apparatus having a control input for adjusting the magnitude of power applied to a load from a source, uses: a sensor responsive to the temperature in the vicinity of the load-control apparatus; a subcircuit for converting the temperature sensed by the sensor to the magnitude of an electrical parameter; a subcircuit for providing a reference electrical parameter having a magnitude predeterminately selected to equal the magnitude of the electrical parameter at a maximum desired temperature T.sub.

Abstract: A touch operated switch for control of electrical lighting, appliances, machinery and equipment which requires non sparking fail-safe operation. The switch utilizes digital complementary metal oxide semi-conductor technology which requires nearly insignificant standby power and incorporates a unique count down reset circuit which prevents extraneous operation from static discharge, radio frequency (RF) signals or power line transients. The switch will only respond to the electromagnetic flux generated by the power source that the controlled load is connected to. All other signals or pulses of differing frequencies are ignored by the switch thereby preventing inadvertent operation. Due to the limited number of discreet components utilized the total cost of manufacture will be extremely low and is expected to be less than the present manufacturing cost of the standard wall-type light switches that this invention will replace.

Abstract: The invention includes a simple and inexpensive thermal controller and simple and inexpensive radio frequency alternating current generator which are provided in an improved temperature control system for a resistively heated electrochemical cell. The temperature controller is formed by a single amplifier with feedback circuit which provides the function of a combined deviation amplifier and two mode (percent proportional band and integral functions) controller. The alternating current generator uses a single direct current voltage source to generate a radio frequency alternating electric current. The two elements are combined in a temperature control circuit for a resistively heated electrochemical cell. The control circuit provides an alternating current with varying power by cyclicly shutting the current off for irregular portions of a predetermined cycle period.

Abstract: This patent presents a touch-responsive switch which incrementally varies AC voltage supplied to an electrical apparatus. The invention includes digital circuitry which compares a control pulse train with a touch affected pulse train to create a switching pulse. The switching pulse is synchronous with the line frequency and controls truncating of individual cycles of line power to regulate voltage applied to an appliance as a function of the number of times a touch plate has been touched. The switching pulse also provides on/off switching as one of the available incremental steps. The circuit components are incorporated in an interface assembly which connects the appliance receptacle to a source of AC voltage.

Abstract: A soft-starting phase-control circuit for controlling both the cold in-rush and normal operating flows of current through a load from an A.C. source. The load may be resistive, may have a non-zero resistance temperature coefficient and may require a load voltage thereacross lower than the voltage provided by the A.C. source connected to the load and the control circuit. The control circuit utilizes at least one power switching device for selectively enabling and disabling the connection between source and load responsive to turn-on and turn-off states of a control signal provided at the output of a gate subcircuit.

Abstract: A monitoring circuit for monitoring the condition of, for example, a remotely situated structure is shown as having a transducer responsive to the occurrence of a preselected condition in the remotely situated structure and effective for causing a signal indicative thereof; timing apparatus actuated upon the occurrence of the signal effective to establish the validity thereof; a power circuit electrically closed upon the expiration of a time span established by the timing apparatus, and sensory warning apparatus actuated upon electrical closure of the power circuit.

Abstract: A pair of comparators, each having the same reference potential at a first input, each have a second input alternatingly receiving different ones of first and second signals relating to the magnitude of a parameter to be controlled. The results of a first comparison, with a first parameter signal connected to the input of the first comparator and the second comparator receiving the remaining parameter signal, is commutated by comparator output circuitry to means for realizing the algebraic difference of the signals and for intermediately storing this difference.

Abstract: Automatic control system for controlling the switching point of a device which operates in at least two modes of operation, provides for automatic modification of the error signal which controls the switching action of the device by processing in real time the error signal to generate a resultant signal representative of the variation of the error signal over a time period, and then employing the resultant signal to modify the effect of the reference signal from which the error signal is derived. The control system can be employed in a chemical analysis instrument to control the on-off operation of a heater which supplies heated air to incubate samples.

Abstract: A system for controlling the temperature at a location which is heated by a heater. The heater is intermittently energized by a source of electrical power in response to control signals from a temperature control circuit. The temperature control circuit includes a comparator-amplifier having one input coupled to a sensed temperature signal. The other input to the comparator-amplifier is a set point temperature level. The sensed temperature signal is produced by a bridge circuit including a temperature sensor at the location which is being heated. The comparator-amplifier includes a feedback network to establish a pulse output of a certain frequency when the two inputs are equal. In order to expand the operating band of the comparator-amplifier, an a-c voltage is introduced superimposed on the set point input.

Abstract: A load and the main conductions paths of first and second TRIACs are connected in series between first and second power terminals across which an alternating voltage is applied. The first TRIAC is for controlling the power dissipated in the load and the second TRIAC is for unconditionally removing power to the load a predetermined time after the first and second TRIACs are turned-on. The first and second TRIACs are interconnected so that the main terminal 1 (MT1) of one is connected to the main terminal 1 (MT1) of the other at a common point. A control circuit for turning-on and turning-off each TRIAC is connected between the gate electrode of each TRIAC and the common point.

Abstract: A battery charger has a control circuit portion and a power circuit portion with common terminals to connect to a battery desired to be recharged, the power circuit includes a transformer and rectifier to deliver at least partially rectified A-C current to the battery, and an A-C power connection through which A-C power is supplied to the power circuit with the control circuit having a solid state switch to selectively connect the A-C power to the power circuit portion. The control circuit portion of the charger has a D-C disconnect feature which senses the interruption in the electrical circuit between the charger's terminals and the battery, said disconnect feature causing the operation of the A-C power switching device to disconnect the A-C power from the power circuit after the terminals have been disconnected.

Abstract: A closed loop phase control circuit. The circuit senses the temperature of a load circuit. It also senses the line voltage on each line of a multi-phase system. The sensed line voltage is full-wave rectified. Comparators for each phase compare an input signal indicative of the temperature of the load circuit with the full-wave rectified line voltage in the corresponding phase and develops an output signal when the full-wave rectified line voltage exceeds the input signal indicative of the temperature of the load circuit. Ultimately, triacs, which are in series with the load for each phase, respond to the existence of an output signal from the corresponding comparators and to a pulse from a timer and conduct in response thereto. When a triac conducts, line current is delivered to its corresponding load resistance. In this way, the time for delivery of line current (and line voltage) to the load resistance varies in accordance with the temperature of the load.