Abstract: In one embodiment, an apparatus is provided for a system including an integrated circuit coupled to a node to receive a supply voltage and having bypass capacitors coupled in parallel with the integrated circuit to the node. The apparatus comprises a first capacitor, a switch coupled to the first capacitor, and a voltage source configured to charge the first capacitor. The switch is coupled to receive a control signal that is asserted, during use, if the supply voltage to an integrated circuit is to be increased. The switch is configured to electrically couple the first capacitor to the node in response to an assertion of the control signal. When electrically coupled to the node, the first capacitor supplies charge to the bypass capacitors. A system comprising the apparatus, the node, the integrated circuit, and the bypass capacitors is also contemplated in some embodiments.

Abstract: A power supply adapted to be coupled in series electrical connection between an AC voltage source and an electrical load for generating a DC voltage, the power supply comprising an energy storage capacitor, the DC voltage produced across the capacitor; a charging circuit adapted to be coupled in series electrical connection between the source and the load and to conduct a load current from the source to the load, the charging circuit coupled to the energy storage capacitor for charging the energy storage capacitor; a controllably conductive device coupled in parallel electrical connection with the charging circuit and having a control input for rendering the controllably conductive device conductive, the controllably conductive device adapted to carry the load current from the source to the load when the controllably conductive device is conductive; and a triggering circuit coupled to the control input of the controllably conductive device for causing the controllably conductive device to become conductive wh

Abstract: In one embodiment, an apparatus is provided for a system including an integrated circuit coupled to a node to receive a supply voltage and having bypass capacitors coupled in parallel with the integrated circuit to the node. The apparatus comprises a first capacitor, a switch coupled to the first capacitor, and a voltage source configured to charge the first capacitor. The switch is coupled to receive a control signal that is asserted, during use, if the supply voltage to an integrated circuit is to be increased. The switch is configured to electrically couple the first capacitor to the node in response to an assertion of the control signal. When electrically coupled to the node, the first capacitor supplies charge to the bypass capacitors. A system comprising the apparatus, the node, the integrated circuit, and the bypass capacitors is also contemplated in some embodiments.

Abstract: In one embodiment, a multi-channel power supply controller adjusts the value of an error signal to minimize overshoot and undershoot during load transients.

Abstract: A switching control circuit for multi-phases PFC converters is provided. It includes a PFC-control circuit coupled to receive a first-inductor signal and a feedback signal for generating a first-switching signal. The first-switching signal is utilized to switch the first inductor for power factor correction. A phase-detection circuit detects the first-switching signal and a second-inductor signal for generating a start signal and a phase-lock signal. The start signal is developed to enable a second-switching signal. The second-switching signal is coupled to switch a second inductor. An on-time-adjust circuit is coupled to adjust the on time of the second-switching signal in accordance with the phase-lock signal. The phase-lock signal is correlated to the period between the end of the second-inductor signal and the start of the second-switching signal.

Abstract: A motor control circuit for supplying power to a DC motor which drives a mechanism having a driven shaft, the control circuit having a parallel combination of a capacitor and switch in series with the DC motor. When the movement of the driven shaft is obstructed, the motor driver and the switch are synchronized in a manner to first charge the capacitor and then to reverse the voltage generated by the motor driver to momentarily double the voltage applied to the DC motor so that the increased torque of the DC motor is able to overcome the obstruction. The mechanism having a shaft driven by the DC motor may be, for example, an ETC valve or a window regulator.

Abstract: An integrated circuit having a bootstrap charger for using in a switching mode power supply is disclosed. In one embodiment, a capacitor is connected between a floating terminal and a bootstrap supply terminal with a voltage drop over the capacitor, a comparing device with a first input terminal receiving a fraction of the voltage drop, a second input terminal receiving a reference, and an output terminal providing a control signal, and a charge circuit configured to charge the capacitor dependent on the control signal.

Abstract: A power supply adapted to be coupled in series electrical connection between an AC voltage source and an electrical load for generating a DC voltage, the power supply comprising an energy storage capacitor, the DC voltage produced across the capacitor; a charging circuit adapted to be coupled in series electrical connection between the source and the load and to conduct a load current from the source to the load, the charging circuit coupled to the energy storage capacitor for charging the energy storage capacitor; a controllably conductive device coupled in parallel electrical connection with the charging circuit and having a control input for rendering the controllably conductive device conductive, the controllably conductive device adapted to carry the load current from the source to the load when the controllably conductive device is conductive; and a triggering circuit coupled to the control input of the controllably conductive device for causing the controllably conductive device to become conductive wh

Abstract: A power supply for a load control device is disposed in series with an AC voltage source and a load and generates a substantially DC voltage for powering a controller of the load control device. The power supply is operable to provide substantially all voltage provided by the AC voltage source to the load and includes a controllably conductive device, a triggering device, and a charging circuit. The charging circuit is operable to charge an energy storage device and to conduct current to the load when the controllably conductive device is non-conductive. The controllably conductive device begins conducting the full load current when the energy storage device has charged to a predetermined amount of energy. Before the controllably conductive device begins to conduct, only a minimal voltage, which is substantially the same as the break-over voltage of the triggering circuit, develops across the power supply to allow the energy storage device to charge.

Abstract: A first constant-current source supplies a charging current to a second terminal of a first capacitor in which a first terminal is grounded. A first terminal of a second capacitor is grounded, and a first switch is provided between the second terminal of the first capacitor and a second terminal of the second capacitor. A second constant-current source supplies current to the second capacitor, and a second switch is provided on a current path of the second constant-current source. A third constant-current source draws out current from the first capacitor and the second capacitor. A switch controller turns on the first switch and turns off the second switch when an output voltage appearing in the second terminal of the first capacitor reaches a predetermined upper-limit voltage. The switch controller turns off the first switch and turns on the second switch when the output voltage drops to a predetermined lower-limit voltage.

Abstract: A programmable capacitor array does not require separate switching transistors because the capacitors themselves have a switchable capacitance, which capacitors are made in the manner of regular N channel transistors with their source/drains connected to each other. When a logic low is applied to the gate, the capacitance is relatively low and the capacitance is what is commonly called parasitic capacitance. The capacitance increases significantly when a logic high is applied to the gate because the logic high has the effect of inverting the channel. Thus, the capacitor array is made of transistors that themselves have switchable capacitance operated so that no separate switching transistors are required. This allows for construction of an array of unit capacitors to achieve monotonic operation and good linearity using conventional manufacturing of N channel transistors while achieving significant area savings and reduced power consumption.

Abstract: Apparatus operates at a power level within a range of power levels that includes a rated maximum power level of the apparatus. The apparatus includes circuit elements to deliver power at an output voltage to a load from a source at an input voltage using an inductor selectively connected between the source and the load during a power conversion cycle. The inductor conducts a current having an average positive value during the power conversion cycle. A first switching device is interposed between the source and a first terminal of the inductor. A second switching device is interposed between a second terminal of the inductor and the load. A switch controller turns ON the first switching device during a time interval within the power conversion cycle during which the current is negative.

Abstract: A power supply circuit is provided that supplies a voltage to a load. The power supply circuit includes a power supply for generating a predetermined voltage; an electrical path for electrically connecting the power supply and the load to each other; a current draw unit for drawing a current from the electrical path; and a current control unit for controlling the current drawn by the current draw unit from the electrical path.

Abstract: A switching regulator has an input terminal for receiving an input voltage, an output terminal for outputting an output voltage, a coil connected between the input terminal and the output terminal, and a slope correcting circuit for outputting a signal adapted to carry out slope correction for preventing current oscillation. An error amplifier compares one of the output voltage and a voltage division value of the output voltage with a reference voltage to output a signal, and a switch controls the output voltage with a signal generated using results obtained by arithmetically operating the output signal of the slope correcting circuit and the output signal of the error amplifier. The slope correcting circuit outputs a signal obtained by adjusting the signal adapted to carry out the slope correction in correspondence to the output voltage.

Abstract: A ramp capacitor CAP1 has a first terminal connected to a power supply voltage VBAT. A generator circuit is connected to a second terminal of the ramp capacitor and adapted to generate a voltage ramp at the terminals of the ramp capacitor. The generator circuit includes a constant current source SCC connected to the second terminal B12 of the ramp capacitor CAP1 and auxiliary circuit MAX adapted in the presence of a transient variation of the power supply voltage to determine the transient current flowing in the ramp capacitor and generated by the transient variation. Responsive thereto, delivery is made to the second terminal B12 of the ramp capacitor CAP1 of a charging current equal to the algebraic sum of the constant current delivered by the constant current source and an auxiliary current equal and opposite to the transient current.

Abstract: An induction heating device includes a plurality of induction coils connected to a single high-frequency power source and each being able to be ON/OFF controlled by a switch. A current is selectively fed only to desired part of the induction coils or to all of the induction coils connected in parallel. The coils are driven by a current fed thereto at the same time in the same phase. The device may include inverters for controlling power to be fed coil by coil. The device is free from interference and irregular heating and can readily cope with a change in a heating range while controlling power coil by coil.

Abstract: The invention relates to a fast-working residual display suppression circuit for LCD and a method thereto. The method includes the following steps: receiving a control signal; if the control signal is an automatic control signal, comparing a first reference voltage with a fixed difference to a supply voltage to a second reference voltage according to an externally input start signal; as the first reference voltage≦the second reference voltage, outputting an activating signal to an LCD power controller and a fast discharge circuit; if the control signal is a manual control signal, directly outputting the activating signal in order to drive the LCD power controller and the fast discharge circuit and cutting off the power supply to the fast discharge circuit by the LCD power controller according to the activating signal and combining two discharge paths of the fast discharge circuit to produce an optimal discharge path to speed up the discharge rate.

Abstract: An analog to digital conversion (ADC) circuit is disclosed including a fully differential reference voltage source. The reference voltage source includes a programmable current supply adapted to drive a programmed current through a resistor so as to establish an initial reference voltage. The initial reference voltage is sampled onto a capacitive network during a first sampling time interval. The capacitive network is coupled to a differential input of a fully differential amplifier, and maintained at a differential output of the differential amplifier during a second output time interval. An output coupling between the differential output and differential input of the differential amplifier acts to maintain stability of the output voltage during the output time interval.

Abstract: An on-die multiple phase power converter reduces output voltage ripple and reduces input current ripple while allowing for higher input voltage and reduced input current to a circuit board. The on-die multiple phase power converter also allows for more than one supply voltage on a die. The converter includes a plurality of single phase switching blocks and a clock signal phase generator. The single phase switching blocks receive phase-shifted clock signals from the clock signal phase generator and provide an output voltage. The output currents of the single phase switching blocks may combine to form a single output to provide current to one or more functional unit blocks on the semiconductor die. One or more or the single phase switching elements may be combined to provide current to one or more functional unit blocks on the semiconductor die.

Abstract: An integrated circuit controller for power conversion systems that provides for the control of parallel phased semiconductor switches without the need for separate filter inductors for each switch. The controller derivates two phased clock signals from a source clock, generates ramp signals, modulates ramp signals, and outputs phased gate drive signals to control parallel phased switches.

Abstract: The invention is directed to a circuit arrangement with an inductive load and a buck converter, wherein the inductive load serves as coil, as well as to an electrical appliance with such a circuit arrangement.

Abstract: A power factor correction circuit arrangement. A rectified alternating-current (AC) input signal may be applied across inputs of a voltage converter circuit, such as a boost converter. Current drawn by the voltage converter may be sensed to form a first sensing signal that is representative of the current. The rectified input voltage may be converted to a second sensing signal that is representative of the AC input signal. Switching in the power converter is adjusted in a first feedback loop to equalize the first and second sensing signals and, thus, the current drawn is regulated to remain in phase with the AC input signal. A feedback signal adjusts switching so as to regulate the output voltage level of the voltage converter in a second feedback loop and, thus, controls power delivered to the load.

Abstract: A main power supply unit 10 of this power supply apparatus for laser comprises asingle-phase rectifying circuit 16 for receiving a single-phase AC voltage E.sub.A at a commercial frequency to convert (rectify) it into a direct current, a capacitor 18 for temporarily storing the DC power from the single-phase rectifying circuit 16, a charging circuit 20 connected between the single-phase rectifying circuit 16 and the capacitor 18, and a lamp current supply circuit 22 connected between the capacitor 18 and an excitation lamp 102. The charging circuit 20 includes a switching element 24 for charging connected in parallel with the capacitor between the single-phase rectifying circuit 16 and the capacitor 18, an inductance coil 26 connected in series between the single-phase rectifying circuit 16 and the switching element 24 for charging, and a diode 28 connected in series between the switching element 24 for charging and the capacitor 18.

Abstract: A motor controlling device for controlling the rotational speed of an AC motor (3) connected with an AC power supply (1) through a speed control thyrister (2) includes a negative charging circuit (5) for charging a negative half cycle voltage of the AC power supply (1) in a negative direction for each cycle to trigger the thyrister (2) in a positive half cycle period of the AC power supply (1), and a positive charging circuit (6) for charging a positive half cycle voltage of the AC power supply (1) in a positive direction from the end of the negative half cycle by the negative charging circuit (5) for each cycle to trigger the thyrister (2) when the charged voltage reaches a trigger voltage of the thyrister (2).

Abstract: A controlled output voltage is provided for a switching mode power converter operating in the continuous conduction mode without requiring a feedback path coupled to monitor the output voltage. Instead, a voltage related to the input voltage is monitored. The monitored voltage is compared to a periodic waveform for forming a switch control signal. In the case of a buck converter operating as a voltage regulator, over each period of the periodic waveform, the periodic waveform is representative of the inverse function. In the case of a boost converter operating as a voltage regulator or buck converter operating as a bus terminator or power amplifier, over each period of the periodic waveform, the periodic waveform has a linear slope. The switch control signal controls a duty cycle of the power switches. Therefore, switching is controlled in an open loop, rather than in a closed loop.

Abstract: A system to alter the voltage supplied to the linear regulator of a pulsed transmitter in accordance with the temperature of the regulator, the minimum voltage required for a transmission and the specific aircraft installation requirements so as to reduce problems of heat dissipation in the regulator.

Abstract: A control system using pulse width modulation, current-mode control to regulate a flyback converter for small input currents. The control system generates a ramp voltage indicative of an input current of the converter with an added bias to overcome the effects of switching noise attributable to parasitic elements in the converter. The ramp voltage is compared with an error voltage is order to obtain the pulse width modulated on-time of a primary switch. Thus, the control system maintains control for small duty cycles of the primary switch by having a control region immune to switching noise.

Abstract: An electrostatic precipitator circuit has an input terminal supplied DC voltage, an output terminal connected to a precipitating capacitor, a storage capacitor connected between ground potential and the input terminal, and a recovery capacitor whose one electrode is applied with ground potential. The circuit further includes a current path switching unit having a common terminal and first and second switch terminals to be connected to the common terminal, the common terminal being connected to a non-ground electrode of the storage capacitor.

Abstract: A circuit for providing a periodic output having a regulated magnitude is derived from a periodic input source. A switch is serially connected to the input for periodically sampling the input at a sampling frequency which is much higher than the frequency of the periodic input, while the duty ratio of the sampling is modulated as an inverse function of the output magnitude. The pulse train of samples is filtered to remove the sampling frequency and its harmonics and the result is a regulated output which replicates the input waveform.

Abstract: Lamp dimmers are disclosed in which, in the course of varying average power supplied to the lamp load, the semiconductor power control devices transition between one and the other of substantially conductive and non-conductive power conditions, the duration of the transition by the power control devices themselves is increased beyond the minimum possible duration to reduce generated EMI. The dimmers disclosed provide for varying the direction, duration, shape, and phase angle of transitions.

Abstract: A lighting control system distributes both the alternating current supply and control signals representing desired adjustments to fixture parameters, such as intensity, via connections including power contacts and, for control signals, an electrically isolating coupling comprising an effective source and detector.

Abstract: A dimmer control circuit for application to a load bank produces a sinusoidal power wave form exhibiting the desirable characteristic of suitable rise and fall times producing little or no audible or radio frequency interference. A pair of MOS-FET power devices operate in a linear mode and attenuate respective half-cycles of a single phase power line as a function of a dimmer control signal applied thereto. The device includes a mechanism for avoiding damage to the power MOS-FET by controlling conditions under which a signal change is applied to the gates of the MOSFETs, and by imbalanced attenuation between the MOS-FETs through the range of the dimmer control signal.

Abstract: A circuit array, adapted to be coupled to a load and a source of a main AC voltage, for reverse phase angle control whereby a current flow in the load is limited to a defined phase angle (.alpha.) of the main AC voltage, comprising the following components for sequential control of the reverse phase angle control: a switching element, connected to the load and coupled to the source of the main AC voltage, for actuating the current flow in the load; a time determining component; and an integrated circuit.

Abstract: A light dimmer with semiconductor power devices coupled between an alternating current supply and a lamp load, in the course of varying average power supplied to the lamp load, transitions the power devices under load between one and the other of substantially conductive and non-conductive conditions, increasing the duration of the transition by the power device itself from the minimum possible duration to reduce generated EMI. Undesirable effects of the high current demands of cold lamp filaments are reduced by initially increasing the conductive portion of half-cycles, relative to the proportion required to produce the desired amount of average power, while avoiding transitions at phase angles that would produce excessive losses. A transition shape may be employed in this mode and in normal operation that maximizes audible lamp noise suppression for a given level of thermal losses.

Abstract: The present invention provides a electronic switch suitable for fading on/off control of electrical equipment like lamps and motors. The main circuit comprises a rectifier bridge circuit and a thyristor. A control circuit includes a fast discharging synchronic integrator and a trigger pulse integrator, the former acts as a pulse phase shifter to provide a self-adapting magnitude variable sawtooth waveform, while the latter acts as a dynamic phase variation memory so as to provide a variable reference for comparison. Trigger pulses which are feed back via the main circuit causes the synchronic integrator to fast discharge. If a control switch is closed, the voltage on the integral capacitor and the trigger angle decreases gradually to produce the fade on. In the fade off process, the conditions are just the opposite. Fading on/off time can be independently set.

Abstract: A low voltage dimmer is shown with the dimming function being on a primary side of a low voltage transformer. Live voltage feeds through a triac to the primary side of the transformer with the gate for the triac being controlled by a microprocessor. To prevent burnout of the transformer if the secondary load side is open, zero crossing of the incoming signal is determined by the microprocessor. If the time constant between the zero crossing of the live voltage and the charging of a capacitor with resistance being provided by the primary side of the transformer exceeds w predetermined time period, the microprocessor will be inhibited from generating a pulse to fire the triac. When the primary side of the transformer has been opened, the load on the secondary side can be re-established, i.e. light bulb replaced. Power for the microprocessor is from the charging of a capacitor used to provide the triggering signal to the microprocessor. Also the microprocessor may be triggered from remote locations.

Abstract: A light dimmer, especially useful for entertainment lighting, provides a high degree of stability in dimmer performance by employing a high level of analog negative feedback and correcting for the undesirable effects on dimmer "curve" by precompensating the input value while it is digital. A lighting control system distributes both the alternating current supply and control signals representing desired adjustments to fixture intensity via a housing common to multiple enclosures. Each enclosure contains at least one dimmer and mechanically engages the housing, from which it obtains a power input via power contacts and a control signal via an electrically isolated coupling comprising an effective source on the housing and detector on the enclosure.

Abstract: A switching regulator including a direct voltage source for producing an input voltage, an electronic switch connected between the voltage source and an output for switching the input voltage to the output, a pulse width modulator connected for controlling the electronic switch, a sawtooth signal generator connected for feeding the pulse width modulator a sawtooth signal of constant maximum amplitude, and a proportional signal circuit connected for feeding the pulse width modulator a signal proportional to current through the electronic switch.

Abstract: An electronic dimming apparatus adapted for use in a distributed dimmer system, the distributed dimmer system comprising at least one alternating current supply; a plurality of lamp loads at spaced apart locations; a plurality of dimmer enclosures, the dimmer enclosures adapted to be located at spaced-apart locations in proximity to the lamp loads, each of the dimmer enclosures containing at least one semiconductor power controller coupled between a power input and a power output, the power output coupled to at least one of the lamp loads by at least one power connector; elongated power conductors coupling the power input of each of a plurality of the dimmer enclosures to the alternating current supply, at least a portion of the elongated conductors disposed within an elongated, substantially rigid enclosure, the enclosure mounting a plurality of power connectors at spaced-apart locations; and a trigger for variably controlling the average power supplied to the lamp load, the trigger responsive to at least a

Abstract: A switch mode electrical power controller arranged to provide a width modulated output pulse signal in response to a control input signal representing a parameter controlled by the power controller, in which a signal processing network for generating the width modulated waveform is arranged to execute all its operations in parallel. The performance, in parallel, of the operations required for the generation of the output signal minimizes the delay along a critical signal path and facilitates high frequency operation.

Abstract: An improved dimming apparatus adapted for use in distribution dimming systems, in which dimmer enclosures each containing at least one semiconductor power controlling means are located in a plurality of spaced apart locations, each such enclosure located in proximity to at least one of its associated lamp loads. The disclosed dimming apparatus achieves unique advantages in the application through the use of a semiconductor power controlling means capable of modulating the instantaneous amplitude of the voltage or current supplied to the lamp load under the active control of its control input, a signal being applied to the control input of the power controlling means such that an output waveform is supplied to the lamp load in which at least one transition between a substantially off condition and a substantially on condition occurs during substantially each discrete half-cycle of the AC source and the duration of the transition is increased to suppress electro-magnetic interference.

Abstract: Disclosed is a device for limiting the inrush current in a lamp, comprising a resistor means to limit the inrush current that may arise in a lamp, the resistor means being connected in series with the lamp and power source; a controlled rectifier (main controlled rectifier) having the main currrent path connected in parallel with the resistor means; another controlled rectifier (secondary controlled rectifier) having the main current path connected with the gate of the main controlled rectifier; and a delay circuit (e.g. RC-time constant circuit) having the output connected with the gate of the secondary controlled rectifier in such manner that the power source energizes the lamp through the resistor means over the time as predetermined by the time constant of the delay circuit.

Abstract: A circuit for controlling power to a load from an AC voltage supply is disclosed. The circuit permits power input to begin at any point either the positive, negative or both halfwaves of an AC waveform and compensates for variations in the AC voltage supply to provide the same power level to the load.

Abstract: A power converter for converting 60 Hertz line power to 20 kilohertz power for driving a low voltage incandescent lamp (42). A field effect transistor power switch section (12) is connected through bridge rectifiers (10, 32) for charging a capacitor filter (34) with the AC input power. A 20 kHz oscillator (38) drives a half-bridge inverter (36) for coupling the capactitor voltage to the lamp (42) as high frequency power. The conduction of the FET power switch (12) is controlled by a phase locked loop (16) for synchronizing the conduction with the zero crossing points of the AC cycle. A ramp generator (18) and a summing network (20) are responsive to a lamp intensity control (22) for changing the conduction duty cycle of the FET power switch (12) such that a desired lamp intensity is maintained.

Abstract: The frequency of an alternating current can be divided with a novel frequency divider, comprising a thyristor connected in series to main current circuit; a counting circuit (e.g. decimal counter or RC-time constant circuit); a trigger circuit for the thyristor, associated with the counting circuit; and a reset circuit. With use of the apparatus, half- or whole-cycle(s) of an alternating current can be supplied to ac appliance at desirable wave intervals.

Abstract: A control circuit for selecting different modes of operation for an outside building light which is operated by interrupting the current to the control circuit from a standard wall switch.The First mode of operation is continuous light for normal use. The second mode produces a flashing light which can be used for alert conditions.The initial application of power from the wall switch always produces the continuous light mode. The second mode can then be selected by switching the power off and then rapidly back on. The control circuit is installed at the light in an adaptor between the bulb and the bulb's socket and can therefore be used without requiring any changes to the switches or existing wiring of the building.

Abstract: An electronic dimming apparatus includes a semiconductor power controller which couples a lamp to an alternating current source and variably controls the average power supplied to the lamp by adjusting the relative proportion of each half-cycle in which the power controller is in a conductive condition. The semiconductor power controller is controlled by the output of a transition controller which in turn is connected to a triggering circuit. The triggering circuit is responsive to a first input condition corresponding to desired average power and also responsive to the zero-crossing of the alternating current waveform. The transition controller gradually changes the condition state of the semiconductor power controller between non-conduction and conduction and controls the voltage across the lamp load to maintain a stable rate of voltage change despite lamp impedance variations, thus reducing electromagnetic interference.

Abstract: A highly efficient circuit for converting a low level DC voltage to the high voltage necessary for energizing a flash lamp. The circuit is very small and non-complex, it is portable and is quickly recharged, particularly being adaptable for emergency flash uses and for toys such as light swords and laser pistols. A very efficient portion of the circuit, comprising a DC/AC inverter, an AC/DC converter and a voltage multiplier, operating at an appropriate frequency, enables the flash capacitor to always be maintained substantially at peak voltage value with minimum power usage.

Abstract: The present invention relates to a phase-regulated zero-crossover ac switching circuit. The present switching circuit comprises the components of (a) regulator having a time constant; (b) ac Wheatstone bridge connected with the regulator and amplifier, which bears in one arm a variable resistance; (c) amplifier for an unbalanced voltage generated in the Wheatstone bridge; (d) means for supplying dc energy to the regulator and amplifier; and (e) thyristor driven by the amplifier, wherein said components are connected in a manner such that said thyristor is not conducted at the moment when an ac power supply is coupled, and that the current through thyristor starts from a zero-crossover of ac sine wave and successively increases to the prescribed level within a period determined by the time constant of the regulator.

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.