Showing papers on "Filter capacitor published in 1978"

Power supply for a high intensity discharge or fluorescent lamp

Abstract: This power supply for a high intensity gas discharge or fluorescent lamp exhibits near unity power factor with no third harmonic distortion, and facilitates highly efficient lamp operation with dimming capability. This is achieved by using an inverter to drive a resonant network that includes the lamp load. A feedback circuit adjusts the switching rate of the inverter to equal the resonant frequency of the network. Sinusoidal output voltage is achieved, together with voltage multiplication to a level sufficient to ignite the lamp and keep it lit during dimming. The inverter is driven by a switching regulator that is supplied with unfiltered, rectified ac power. A filter capacitor, connected across the regulator output, is sufficiently large so as to filter at the frequency of the rectified ac input. The regulator switching duty cycle is controlled in response to the average dc level across this filter capacitor. Lamp dimming is achieved either by adjusting the switching regulator dc output level or by varying the duty cycle of the inverter. The high power factor low distortion regulator concept may also be applied in other application where direct current power is derived from an ac line.

DC to DC voltage converter

Abstract: The DC to DC voltage converter consists of two single ended pulse width modulated converters with a single voltage control loop, a power balancing control loop and overload protection circuitry. The converters which share the same input and output filters are staggered in time so as to reduce the pulse current in the input filter capacitor and the ripple current in the output filter capacitor thereby permitting a reduction in the size of the input and output filters.

Reliability Evaluation and Failure Analysis for Multilayer Ceramic Chip Capacitors

Abstract: Reliability evaluation tests for multilayer ceramic chip capacitors mounted on a hybrid IC were implemented. Failure modes, failure mechanisms, and drift of characteristics were analyzed. Humidity acceleration as well as voltage and temperature accelerations were investigated to estimate the chip capacitor reliability. The chip capacitor reliability proved to be high and adequate for the service period of the communication system.

True noninverting integrators with single grounded capacitor

Abstract: Four new active integrator configurations are reported. All the circuits use single grounded capacitors.

High-Frequency Measurement of Q-Factors of Ceramic Chip Capacitors

Abstract: No reliable instrumentation systems have been available for the measurement of capacitor properties, particularly Q-factor, in applications requiring operation in the 100-1000 MHz range. The production of large numbers of multilayer ceramic chip capacitors for such special use is a very recent development. The need for reliable measurement equipment is increasing both for purposes of device evaluation and device development. A high-Q transmission line has been constructed, and a mathematical system has been devised for employing that line in a resonant mode to determine capacitor parameters, and particularly Q-factor, at the range up to and including microwave frequencies. The device produces accurate reliable data. The equipment can be reproduced and the system can be used in analysis and evaluation with a degree of confidence not possible in the past.

Band-pass filter

Abstract: A bandpass filter is disclosed which includes a low-pass filter and an analog delay circuit in which the delay time is set by a clock signal. THe analog delay circuit samples the voltage of the low-pass filter capacitor and delays the sampled voltage according to the clock signal. The output of the analog delay circuit is then used to equalize within a certain period of time the voltage of the low-pass filter capacitor. The analog delay circuit may consist of an integrated circuit BBD (Bucket Brigade Device) or CCD (Charge Coupled Device).

Circuit for reducing transients by precharging capacitors

Abstract: A variable filter having a plurality of different loopwidths is disclosed. The variable filter, which is typically employed in a phase locked loop, includes a plurality of capacitors which are switchably coupled into and out of operation in the filter in order to change loopwidths. Those of the capacitors which are not currently operational in the filter are precharged so as to prevent loss of lock in the phase locked loop when switching to another loopwidth.

Capacitor DF and Q

Abstract: Although the impedance characteristics of capacitors have been well known for years, it appears that the dissipation factor (DF) and Q have not been directly related to the capacitor model. This can be easily done and provides new insight into capacitor characteristics. Impedance paper can be used so that the impedance, dissipation factor, and Q can be drawn by inspection.

Switching regulator for television deflection circuit with improved ultor voltage regulation

Abstract: A horizontal deflection circuit drives a deflection winding and an ultor voltage generator. The energizing voltage for the horizontal deflection generator is regulated by a switching regulator including an SCR, a filter inductor, a filter capacitor and an SCR turn-off winding. The turn-off winding couples a retrace pulse to the SCR during each horizontal retrace interval to turn the SCR off in preparation for the following regulation interval. A second winding is magnetically coupled to the deflection circuit and through a diode to the filter inductor for providing a path by which current can continue to flow in the filter inductor during SCR nonconduction and which effectively couples the filter inductance across the deflection winding. Variations in kinescope beam current cause corresponding variations in the current through the filter inductor at the end of the trace interval. The current variations in the filter inductor cause the diode to become nonconductive at times during the retrace interval which are related to the beam current, thereby changing the average time during which the filter inductor parallels the deflection winding and varying the retrace pulse duration in such a manner as to improve the ultor voltage generator regulation.

150 kVA samarium cobalt VSCF starter generator electrical system. Final technical report, 1 June 1974-31 May 1978

Abstract: This report documents the development, construction and test of a 150 KVA Starter/Generator Variable Speed Constant Frequency (VSCF) electrical system which includes a solid rotor machine using rare earth samarium cobalt magnets. The system consists of the solid rotor 14-pole starter/generator which in the generate mode, is driven at 12,000 to 21,000 RPM and a cycloconverter which, converts the 9-phase variable frequency power from the generator to a high quality 3-phase, 400 Hz, 150 KVA power source. In the start mode, the cycloconverter converts 3-phase, 400 Hz power to a 9-phase variable frequency, variable voltage which is used to power the starter/generator as the equivalent of a brushless DC motor. The rotor was developed during the first phase of the program which is reported on in detail in AFAPL-TR-76-8. The generator is oil cooled and uses a selfcontained oil pump. It also includes a high speed mechanical disconnect which is solenoid operated to remove drive power and is mechanically reset at zero speed. The stator core uses 0.006 inch permendur laminations to handle high flux densities with a minimum of eddy current losses. The cycloconverter uses a dip brazed chassis, with liquid (oil) cooled cold plates for heat extraction. Themore » major volume in the converter houses the power handling components which include 54 SCRs, 18 interphase transformers, 15 output filter capacitors and input despiker components.« less

150 KVA Samarium Cobalt VSCF Starter Generator Electrical System

Abstract: : This report documents the development, construction and test of a 150 KVA Starter/Generator Variable Speed Constant Frequency (VSCF) electrical system which includes a solid rotor machine using rare earth samarium cobalt magnets. The system consists of the solid rotor 14-pole starter/generator which in the generate mode, is driven at 12,000 to 21,000 RPM and a cycloconverter which, converts the 9-phase variable frequency power from the generator to a high quality 3-phase, 400 Hz, 150 KVA power source. In the start mode, the cycloconverter converts 3-phase, 400 Hz power to a 9-phase variable frequency, variable voltage which is used to power the starter/generator as the equivalent of a brushless DC motor. The rotor was developed during the first phase of the program which is reported on in detail in AFAPL-TR-76-8. The generator is oil cooled and uses a self-contained oil pump. It also includes a high speed mechanical disconnect which is solenoid operated to remove drive power and is mechanically reset at zero speed. The stator core uses 0.006 inch permendur laminations to handle high flux densities with a minimum of eddy current losses. The cycloconverter uses a dip brazed chassis, with liquid (oil) cooled cold plates for heat extraction. The major volume in the converter houses the power handling components which include 54 SCRs, 18 interphase transformers, 15 output filter capacitors and input despiker components.

Protector for controller of chopper

Abstract: PURPOSE:To reduce the capacity of filter capacitor in a power source circuit by shortening to a great extent the time interval from the reduction of chopper control voltage to chopper off.

Capacitance to digital conversion system

Abstract: A capacitance to digital conversion system wherein condition sensing capacitors and reference capacitors are arranged with circuitry including a virtual ground and means for providing an error signal related to the sensed condition. The capacitors, virtual ground and error signal means are disposed within a sealed housing so that the system is isolated from environmental influences and is hence more stable than like systems known in the art.

Recovery Voltage Measurements with Emphasis Below One Second for Class I NPO Ceramic Capacitors

Abstract: It has been known for some time that dielectric absorption in the integrator capacitor constitutes a fundamental limitation on the accuracy of analog electronic integrator circuits. However, little dielectric absorption information is available for monolithic ceramic chip capacitors. Yet, such ceramic chip capacitors appear to be the only alternative for most applications where hybrid construction techniques are required. To provide insight into the possibility of using ceramic capacitors in such applications a number of recovery voltage measurements were made using NPO-type ceramic capacitors. The limits of the results are reported. Particular emphasis is given to the interval below one second. The technique used to perform the measurements was based on the method described by Dow. The apparatus used to make the measurements is described.

Square pulses, DC, and impulse corona measurements on high voltage capacitors for power electronics

Abstract: A new method of measuring corona under DC, impulse, and square pulses at high repetition frequencies has been developed. It involves the use of the electret effect. It has been applied to high voltage metallized Mylar, mica paper impregnated with epoxy and to low voltage metallized single film PVF2 capacitors.

Stabilised DC voltage supply for TV receivers - has switching stage coupled to filter capacitor supplying output load

Abstract: The generation of a stabilised d.c voltage for t.v receiver applications is achieved using a filter and switching stage. The unsmoothed d.c inpt is coupled to a variable inductance (2) with the output connected to a transistor switching stage (3). The load (6) is supplied over a filter capacitor (4) and the switching stage is cycled at 20 kH2 by a signal generator. The stabilished d.c output is determined by the capacitor characteristic and the periodic operation of the switching stage. Voltage level is determined by the potentiometer (9) voltage (U3) applied to the inductance.

Static energy reserve for static voltage converters in rail vehicles - has capacitor connected through high resistance to supply wire

Abstract: The device has an auxiliary capacitor for current supply before the converter input filter. Its capacitance is much greater than the total capacitance of the input filter capacitors. This capacitor is connected through a resistor to the supply wire. The resistor resistance is so high that the capacitor can be continuously supplied with h.v. even in case of a short-circuit in the capacitor. It is, therefore, designed for the line overvoltages. This overvoltage is a fraction of maximum permissible overvoltages. The capacitor is statically connected to the converter only when the current collector is not in contact with the contact wire. Thus the capacitor is slowly charged when the current collector is in a continuous contact with the contact wire, and delivers energy to the converter during brief interuptions of the current supply.

Push-Pull Accumulator using Switched Capacttors

Abstract: Accumulators are used for sampled data signal processing. They can be implemented either with switched capacitors /1/ or with charge transfer devices /2/. Switched capacitor accumulators offer the advantage of simple MOS technology and higher operating frequencies since no shift register operations are necessary but only potential equilibration between capacitors is required to obtain the desired transfer function, furthermore transfer losses do not modify the attenuation characteristics.

High voltage power supply

Abstract: PURPOSE:To obtain a high voltage power supply to eliminate electrostatic induction voltage by inserting a coupling capacitor which is symmetrical to each other into the input end of a bridge recifier circuit and a filter capacitor into the output end and generating DC voltage.

An Evaluation of the Voltage-Current Rating Characteristics of Miniature Monolithic RF Ceramic Capacitors

Abstract: This paper reviews the establishment of RF voltage and current rating characteristics of monolithic ceramic capacitors, using thermal balance considerations between heating of the component due to dielectric losses and heat transport through conduction by the electrodes.

Supply of load with variable DC from AC mains - has capacitor in bridge connected to AC terminals through controlled diodes

Abstract: A rectifier bridge is connected to the ac mains (6) its output being connected to the load, and its diodes (13a,14a, 21, 22) are connected in a bridge, with at least the diodes in one bridge half being controllable and forcibly extinguished. It has further a being connected to the load, and its diodes (13a,14a,21,22) filter capacitor in parallel with the rectifier ac input terminals. The filter capacitor (20) is connected to the mains side terminals (8, 9) through non-controlled diodes (21, 22) in the bridge series arms. In another arrangement, a filter capacitor is also connected in the other half of the rectifier bridge.

Chopper control device for electric car

Abstract: PURPOSE:To prevent the voltage across a filter capacitor from suddenly rising by connecting in parallel a thyristor to a braking resistor and by controlling the conductivity of the thyristor in accordance with the voltage across the terminal of a main motor.

Degradation of PVF2 Capacitors During Accelerated Tests

Abstract: Since the advent of metallized paper capacitors a continual effort has been made to produce thinner dielectric films with higher dielectric constants in order to obtain smaller sized capacitor for a given capacitance. The long list of materials used includes some of the following; mylar, nylon, teflon, polyester, polytetrafluoro-ethylene, polypropylene, polycarbonate, polyvinyl chloride,and more recently,polyvinylidene fluoride (PVF2). The dielectric constant of PVF2 is approximately 11 compared to others on the above list which. range between 2 and 4; hence the attractiveness of PVF2.

Output current sensing device for dc power supply

Abstract: PURPOSE:The output current of DC electric current and a charging or discharging electric current in the filter capacitor are sensed at a level of AC electric current, combined with each other and then used for providing a precise sensing of the output current in DC power supply.

Surge protection of full-wave rectifier by biased ionization tube

Abstract: A television receiver includes a full-wave rectifier and filter capacitor coupled to the A.C. power line for generating an unregulated direct operating voltage for the receiver. In order to provide a start-up voltage for certain portions of the receiver when the receiver is initially turned on, a transformer has a primary winding coupled between the rectifier and the filter capacitor which is responsive to the initial surge current in the capacitor. In order to protect the diodes of the rectifier from voltage surges which may enter the receiver from the A.C. line, a glow or ionization lamp is coupled across the primary of the start-up transformer. The glow lamps have unpredictable start-up voltages when operated in the dark interior of the receiver housing. The lamps are ionized independent of the presence of surges by coupling to the horizontal deflection circuit. With independent ionization of the glow lamp, the voltage drop and speed of response to surges is improved.

Encapsulating solid tantalum capacitors

Abstract: Powdered plastic encapsulation of solid tantalum capacitors is achieved through coating the capacitors between 150° C. and 250° C. while biasing the capacitors at direct voltage between 0.2 and 1 times the rated voltage. The plastic is cured in about 3 minutes. The capacity temperature derating and the reverse current temperature derating are reduced with respect to capacitors encapsulated unbiased at the same temperature.

Sampled Data Simulation of Large On-Chip Capacitors and Inductors for Audio Filtering Applications

Abstract: Large on-chip capacitors and inductors have been realized by means of sample and hold functions. They are based on the backward-Euler integration rule of their current-voltage relation.