Showing papers on "Decoupling capacitor published in 1978"

Analytical Method of Capacitor Allocation on Distribution Primary Feeders

Abstract: This paper reports the development of an analytical method to determine the best capacitor locations, reactive compensation level, and yearly loss reductions under a wide range of annual reactive load conditions for use in distribution system design. The results show that, not only is more than 80 percent yearly loss reduction possible with non-switched capacitor banks, but also optimum reacttve-compensation level and maximum yearly loss reduction can be expressed in a simple mathematical equation.

Single slope A/D converter with sample and hold

Abstract: A converter circuit employs a capacitor coupled through a selector switch to an analog voltage so that the capacitor is charged to the analog level. When a conversion is commanded, the capacitor is disconnected from the analog voltage and discharged through a constant current load. This results in a linear voltage ramp. A comparator senses the capacitor voltage and compares it to a reference level that is slightly above ground. Upon starting the ramp an increment of voltage slightly larger than the reference is applied in series with the capacitor. When the ramp drops below the reference level the comparator output is used to terminate the conversion interval. Thus, the conversion interval is directly and linearly proportional to the magnitude of the analog voltage. If desired, the conversion interval can be used to operate a counter to provide a conventional digital readout. Alternatively, the device can be operated by a microprocessor with the readout being sensed and displayed if desired by the microprocessor. Due to the increment of voltage, the zero analog voltage conversion interval is a fixed finite time.

Circuit arrangements for the control of a bistable relay

Abstract: Circuit arrangements for the control of a bistable relay having a capacitor connected in series with the relay coil. The series connection of the coil and the capacitor is connected to an excitation voltage for actuating the relay and simultaneous charging of the capacitor. When the excitation voltage is removed, the series connection is short-circuited through a semiconductor switch, whereby the capacitor is discharged and the relay switched back to its initial position. The bistable relay is thus operated as monostable relay.

Power up circuit with high noise immunity

Abstract: A power up circuit for an associated digital circuit is disclosed which prevents noise from falsely resetting the associated digital circuit after completion of the powering up function. The power up circuit has a series connection of a first capacitor and a high impedance coupled between the power supply and ground. The high impedance is connected in parallel with the source and drain electrodes of an enhancement type field effect transistor. The node of the high impedance and the first capacitor is connected to an inverting amplifier which produces an inverted output after the input signal falls to a threshold potential. The output of the inverting amplifier is connected to the gate of the field effect transistor and to a second capacitor which is connected to ground. The output of the inverting amplifier is applied to the reset line of the associated digital circuit to cause resetting of the digital circuit upon the connection of the power supply to the digital circuit. After powering up, the field effect transistor is biased on by the output of the inverting amplifier. Any noise pulses which are coupled to the first capacitor are shunted to ground by the low impedance of the turned on field effect transistor.

Driving circuit for integrated circuit semiconductor memory

Abstract: An improved driving circuit is provided especially for use in an integrated circuit semiconductor memory which operates on low power supply voltage, such as 5 volts, the drive circuit employing field effect transistors coupled with bootstrap capacitor devices and responsive to an input pulse for supplying, at its output terminal, a pulse having a peak voltage potential substantially equal to the power supply voltage value despite the inherent threshold voltage drops of the field effect transistors utilized. In the drive circuit, in response to an input pulse, the reference voltage for charged capacitor devices is switched between a first level and a raised second, higher level to place the capacitor devices in series with each other and the raised reference voltage to overdrive an output switch device so as to connect substantially its full power supply voltage to its output terminal during a corresponding output pulse.

Method and apparatus for testing electrolytic capacitors

Abstract: An Equivalent Series Resistance (ESR) measurement device for testing electrolytic capacitors without removing the test capacitor from the circuit in which it is being used and without first discharging the test capacitor prior to testing. A low voltage AC ohmmeter, which operates at a frequency of approximately 100 KHz, is used as the measurement device for the in-circuit testing of the ESR and thus as an indication of the status or usability of the electrolytic capacitor being tested. A current-blocking capacitor is placed in series with the electrolytic capacitor being tested to allow in-circuit testing without damaging the meter since it blocks any DC charge remaining on the test capacitor. A pair of oppositely poled diodes are coupled in parallel across the terminals of the meter to protect the meter from surge currents and the like and a resistor is coupled in parallel with the test capacitor to provide a discharge path for discharging the series blocking capacitor when the electrolytic capacitor is removed from testing. The ESR meter itself is designed with two operational amplifiers forming an oscillator whose output is relatively immune from fluctuations in supply voltage. An amplifier network including three operational amplifiers is provided to amplify the ESR signal to a usable level. A peak-to-peak detector circuit is used which employs an operational amplifier having a supplemental feedback resistor which reduces the phase shift at the output of the operational amplifier to enable the peak detector diodes to perform their conventional functions. The two outputs of the peak detector are connected to two DC amplifiers and a conventional meter movement is driven differentially by the DC amplifiers to provide a visual readout of the measured ESR of the test capacitor for evaluation purposes and the like.

Solid state tunable capacitor

Abstract: A semiconductor tunable capacitor is described. This tunable capacitor employs a plurality of metal-insulator-semiconductor (MIS) capacitive segments and each element has a first and a second value of capacitance. The solid state capacitor employs a plurality of tuning terminals and a single capacitor terminal. Tuning signals are applied to each of the tuning terminals for switching that capacitive segment into its high or low capacitive state. The capacitor terminal is capacitively connected to each capacitive segment and is employed for summing the individual values of capacitance into a total value of capacitance. An MNOS capacitor is shown as the preferred embodiment.

Length measuring system

Abstract: An electrical length-measuring system comprises two capacitors and electronic means for obtaining an indication voltage proportional to the displacement. The measuring capacitor, whose capacitance is varied in a linear manner by the displacement to be measured, is connected to a reference a.c. voltage, whilst the reference capacitor with the same dielectric is connected to a measuring a.c. voltage of the same frequency and opposite phase, whose amplitude can be varied by electronic means in such a way that the a.c. voltage induced on an electrode common to both capacitors becomes zero, forcing the measuring a.c. voltage to be proportional to the displacement. Preferably the capacitance change of the measuring capacitor is brought about by an earthed screen inserted between both electrodes. In the system specifically described and illustrated, the measuring capacitor comprises two coaxial cylindrical electrodes and a coaxial cylindrical screen is inserted axially between the electrodes as a function of the displacement. In the described and illustrated system also, the a.c. voltages are of a rectangular nature, making it easy to eliminate errors due to transient couplings.

Demodulator circuit for chopper amplifier

Abstract: In a demodulator circuit for a chopper amplifier including a rectifier and a smoothing filter having a capacitor, an impedance conversion circuit is connected to the output side terminal of the capacitor to ensure holding of the stored charges of the capacitor at each negative half-cycle of the amplitude-modulated AC signal applied to the demodulator circuit. A discharge circuit including a switching element is further provided for the capacitor and the discharge circuit is rendered conductive at each positive half-cycle of the amplitude-modulated AC signal which is also applied to a control terminal of the switching element.

A New Series Capacitor Protection Scheme Using Nonlinear Resistors

Abstract: A new series capacitor protection scheme that limits capacitor overvoltages by inserting a nonlinear resistor in parallel with the capacitor bank during faults is presented. The concept of operation, prototype installationad field test performance evaluation are discussed.

Power supply for flash lamp

Abstract: A power circuit for a discharge lamp, in particular a flash lamp serving as light source in an optical analysis apparatus which comprises an electric power source outputting a d.c. voltage and capable of reabsorbing electrical energy, which also comprises an energy transferring circuit inserted between the electric power source and a first capacitor connected to the lamp, the capacitor being charged via the energy transferring circuit and adapted to store the energy required for each discharge across the lamp, the energy transferring circuit comprising a first current path comprising the primary winding of an autotransformer and adapted to transfer current from the electric power source to the first capacitor until the voltage across it reaches a predetermined value, and a second current path comprising a second capacitor for storing part of the surplus or non-used energy stored in the autotransformer during the charging of the first capacitor. To reduce interalia the duration of the charging cycle of the first capacitor, the energy transferring circuit further comprises a third current path comprising the secondary winding of the autotransformer, which path serves for returning the unused energy stored in the autotransformer and in the second capacitor to the electric power source.

Data imprinting lamp control circuit

Abstract: A lamp control circuit for energizing a data imprinting lamp in response to an actuation of a flash trigger switch in a camera, for a given period so that data images illuminated by the lamp are imprinted on a film with a suitable exposure. The control circuit includes a series connection of a SCR element and a capacitor, a trigger circuit for applying a single pulse to the control terminal of the SCR element, a capacitor discharge circuit for discharging with a given time constant the capacitor that has been charged through the SCR element, and a switching circuit for energizing the lamp while the terminal voltage of the capacitor is above a threshold level. The trigger circuit has a high input impedance to protect the control circuit from high voltage which otherwise may be applied thereto through a camera synchro terminal to which the input terminal of the trigger circuit is connectable.

Negative resistance oscillator working in ghz range - has dielectric resonator connected to negative resistance element and mounted on dielectric substrate

Abstract: The negative resistance oscillator works in the GHz region. The oscillator is based on a dielectric resonator associated with a negative resistance element. The resonator, normally cylindrical, has one metallised end face mounted on an isolating substrate (2) such as alumina or silica. The substrate is laid on one inside surface of an 'L' cross section base (40) which carries on its remaining face a variable capacity diode (50) or varactor, e.g. a Schottky diode, a decoupling capacitance (7) to earth and a second decoupling capacitor (9). Both capacitors are in parallel and spaced by about a quarter wavelength of the oscillator frequency forming a low - pass filters. The positive supply is taken to earth and the negative to one side of the diode.

Frequency tracking adjustable duty cycle ratio pulse generator

Abstract: A frequency tracking, adjustable duty cycle ratio pulse generator that accepts an incoming stream of equally time spaced spike pulses, which go to a first input of an OR gate. The output of the OR gate is fed back to a comparator which has a reference voltage on one input terminal, and receives the feedback voltage from the output of the OR gate through a first switch and through a capacitor. There is a shunt circuit around the capacitor that includes a series resistor and a second switch. The output of the capacitor also connects to a second resistor, to ground. In operation, the first switch is closed when the output of the OR gate is high and when the first switch is closed, the second switch is open, and vice versa. The duty cycle ratio is dependent upon the rate of charge of the capacitor, which is controlled by the capacitance and the second resistor. The period of the output pulses is controlled by the discharge of the capacitor through the first resistor, which is determined by the time constant of the capacitance and the first resistance. A second embodiment has an OR gate which serves not only to control the pulsing of the output circuit, but also provides the reference voltage which controls the pulsing.

Integrator circuit with limiter

Abstract: An integrator circuit is disclosed, comprising a capacitor, at least one connectable and disconnectable power source for charging and discharging the capacitor, and a limiter device comprising diodes for limiting the capacitor voltage to a predetermined value. The limiter device can be separated from the remaining integration circuit, thus avoiding the effect resulting from the current/voltage characteristic of the diodes, particularly undesirable voltage discontinuity.

Adjustable time delay relay

Abstract: An adjustable time delay relay is provided which is particularly suitable for automatic transfer switches and other applications requiring a relatively long time delay during periods when electrical power is not available The relay includes a relay coil connected across a large storage capacitor supplied from an AC power source through a diode The timing function is provided by a separate timing capacitor which, upon discharge through an associated adjustable resistor, operates a switching transistor to establish a low impedance path across the relay coil, thus discharging the storage capacitor and de-energizing the relay Such a construction eliminates the need for a close tolerance, high value storage capacitor and provides a high degree of time delay reproducibility despite variations in power supply voltage

Multiple flashlamp operating circuit

Abstract: A DC circuit for efficiently operating two arc discharge flashlamps. The lamps are parallel connected across a single supply storage capacitor, and a single trigger capacitor is employed in connection and the two alternately activated trigger sources for the two lamps.

Power supply circuit for a subscriber's telephone set

Abstract: A power supply circuit for providing a local power supply replenished from the exchange for a telephone instrument. An electrical energy storage device is connected in parallel with an impedance by a device providing a unidirectional transfer of electrical energy from a direct current path through the impedance. A by-pass circuit is connected in parallel with the impedance. The impedance is a zener diode, the storage device is a capacitor, the unidirectional transfer device is a diode, and the by-pass circuit is a transistor responsive to the state of charge of the capacitor. A trickle charge circuit is connected to transfer energy to the capacitor irrespective of the by-pass circuit and a speech-frequency by-pass circuit is in parallel with the zener diode. A switch responsive to on-hook/off-hook conditions is used to confine energy storage to off-hook periods.

Flyback type power supply

Abstract: A flyback type power supply in which dissipation losses associated with switch transition time are substantially eliminated by performing all switching operations at or near zero current by the use of a plurality of resonant circuits. In a first resonant circuit an intermediate storage capacitor is resonantly charged through an inductor and a first switch until, after a half sinewave of charging current, the voltage on the capacitor is twice the input supply voltage. The capacitor is then discharged through a second switch and the primary inductance of a flyback transformer having rectifiers on the secondary that are back-biased initially so as to provide a resonant current buildup in the primary winding with an amplitude that follows a sinewave function, the primary voltage following a cosine function. At the peak of the sinewave of current in the primary, the voltage across the transformer reverses in polarity, continuing to follow a cosinewave shape until the secondary voltage exceeds the voltage on the network to be charged. The primary current is then discontinued and the remaining energy stored in the transformer inductance is transferred to the circuit to be charged.

Telephone status monitor circit

Abstract: A telephone status monitor circuit for determining the on/hook and off/hook conditions of a telephone connected across standard tip and ring terminals of a telephone system. The telephone status monitor circuit includes a charging circuit, in the form of a series combination of a capacitor and a resistor, which is adapted to be alternately and periodically switched in and out of circuit with the tip and ring terminals. When the charging circuit is in circuit with the tip and ring terminals, the capacitor is charged to the value of the voltage across the tip and ring terminals. When the charging circuit is out of circuit with the tip and ring terminals, the charging circuit is coupled to additional circuitry which examines the value of the voltage across the capacitor. If the value of the voltage across the capacitor corresponds to an on/hook condition, a first output signal is produced by the additional circuitry. If the value of the voltage across the capacitor corresponds to an off/hook condition, a second output signal is produced by the additional circuitry.

Induction heating inverter

Abstract: A static power supply for converting DC power from a source to AC power at relatively high frequencies in a load. The static power supply is particularly useful for supplying power to induction heating loads operating at frequencies of 10 kHz. and higher. The DC supply is connected to supply substantially constant current to a controlled rectifier switching circuit. The controlled rectifiers are gated to produce alternating current in a commutating capacitor. The DC supply and switching circuit are connected to the load via a blocking capacitor so that the AC current component in the switching circuit appears as high frequency AC load current. The circuit arrangement imposes low operating stress levels on the controlled rectifiers, and provides a circuit turn-off time that is relatively independent of load.

Multiple variable phase control circuit

Abstract: A temperature control circuit for a point-of-use water heater comprises a pulse charging circuit which includes a summing capacitor provided with a residual charge thereon at the beginning of each half cycle of an a.c. supply. The residual charge on the summing capacitor determines the pedestal charge on a timing capacitor and thereby the phase angle at which a ramp superposed on the pedestal fires a programmable unijunction transistor to provide a pulse for triggering switching means to supply a fraction of the a.c. supply to the heater each half cycle. The residual charge on the summing capacitor is determined each half cycle by the discharging thereof in accordance with a load current pulse feedback circuit and the output of a comparing circuit which compares the actual temperature of the water flowing past the heater with a desired set temperature.

Stereophonic system having power amplifiers and speakers in a bridge circuit with capacitor connecting junction of speakers to common terminal

Abstract: Left and right stereo power amplifiers receive power from the 12-volt D.C. automobile supply bypassed by a single capacitor for both amplifiers and energize left and right loudspeakers in series with the junction of the series-connected speakers coupled to ground through a capacitor that allows the left and right speakers to be independently driven by the left and right power amplifiers, respectively, by spectral components above the crossover frequency determined by the speaker impedance and the capacitor impedance. Each power amplifier is driven by an equalizing circuit including a photocell illuminated by an LED that is driven by a feedback signal from the power amplifier.

Voltage regulator, particularly for automotive use

Abstract: To improve the regulating response of an automotive-type, solid-state voltage regulator and render it essentially immune to ripple while additionally permitting complete integration of the entire voltage regulator without external discrete filter capacitors, a difference amplifier has the output voltage of the on-board vehicle network, for example from an alternator, applied thereto for comparison with a reference, the difference amplifier, respectively, controlling a capacitor charge current supply and a discharge current drain circuit, both connected to a small capacitor in the order of, for example, only 30 pF which, hence, can be integrated, the voltage across the capacitor being sensed in a high-low window or range-type discriminator which has a dual-state output to control conduction or non-conduction of a transistor in series with the field of the alternator in dependence upon whether the voltage across the capacitor, as it is being charged or drained, is above an upper threshold or below a lower threshold of the discriminator. Preferably, the circuit includes current mirror circuits in which currents in one branch are reflected in another to provide for balance, temperature compensation, and to render the circuit immune to variations in loading on the alternator.

Power supply providing constant power output

Abstract: A power supply for developing substantially constant average power in a variable resistance load (18) from an alternating polarity source (11) comprises an AC portion including serially connected capacitor means (12), and a DC portion including rectifying means (20) for providing a polarized signal to load resistance (18) and inductor means (17) for maintaining a charging current through a path including capacitor means (12). The constant average power mode obtains when the range of values of load resistance (18) is less than a network parameter determined from the frequency of source (11) and value of capacitor means (12).

Combination capacitor and transistor structure for use in monolithic circuits

Abstract: A combination capacitor and transistor structure is described wherein the capacitor is formed integrally with the emitter electrode of the transistor. The transistor is formed in a monolithic integrated circuit using generally known techniques and constitutes a vertically integrated PNP device. The emitter electrode of the transistor which comprises a P+ diffusion region is of a predetermined area which is large enough to form the bottom plate of the capacitor. The top plate of the capacitor is formed by growing a dielectric material over the diffused emitter region and then forming metallization thereover. The combination capacitor and transistor structure may be utilized in a bias network for biasing the output stage of an operational amplifier in a class AB mode. The capacitor formed in the combination structure may be utilized as the compensation capacitor in such operational amplifier which utilizes pole splitting techniques. The improvement provided by the invention reduces the surface area of the semiconductor die chip required to form the capacitor and transistor which facilitates greater device density on a particular die chip.

Voltage regulated capacitive discharge welding power supply

Abstract: A welding power supply that includes a combination of series and shunt regulating circuits controlled by a single controller, in the charging circuit for a welding energy storage capacitor. The series circuit, which includes a series thyristor, regulates the supply of charging energy to the capacitor from a full wave rectified power source. The series circuit also phases forward to replenish charge lost by leakage by controlling the thyristor firing angle as a function of the difference between the capacitor charge and a pre-selected value. The shunt regulating circuit utilizes a shunt thyristor coupled to the output of the power source to divert energy delivery away from the energy storage capacitor when a preselected charge level on the capacitor is reached. The shunt regulating circuit shorts out the unneeded balance of the charging cycle thereby eliminating capacitor voltage overshoot during the charging process.

Control circuit for a direct current motor

Abstract: A control circuit for a direct current electric motor including a rectifying bridge for supplying the motor with direct current and a regulating circuit including a triac, the energizing angle of which is determined by a capacitor connected in series with a resistance network. An energy limiting circuit is provided including a resistance connectable in series with the resistance network and the capacitor when the voltage exceeds a predetermined value so that the motor can be operated on a 110 V or a 220 V supply.

DC Power source

Abstract: A DC power source is provided with a rectifier circuit connected to an AC power source and a smoothing circuit, which is comprised of a DC reactor and a parallel capacitor, connected to the output terminal of the rectifier. A load is connected to the parallel capacitor. A diode is connected in a closed circuit including the parallel capacitor and the load, with such a polarity as to check discharging current discharged from the parallel capacitor. The diode forms the closed circuit, together with an auxiliary power source for applying through a reactor to the diode a voltage to make the diode conductive in forward direction. In short-circuiting accident of the load, a conducting circuit established between the auxiliary power source and the diode is shut off to block an excessive current flowing through the diode into a short-circuiting path between the parallel capacitor and the load.