Showing papers on "Parasitic capacitance published in 1974"

An ultrasonic imaging system for realtime cardiac imaging

Abstract: Realtime, non-invasive imaging of cardiac structures and other internal body organs, accomplished with an ultrasonic imaging system, will be discussed. The approach utilizes custom integrated circuits including high-voltage double diffused MOS transistors.

Electronic circuit module with printed circuit board and grounding means

Abstract: A modular housing for an electronic circuit having a low profile compatible with planar circuit boards and arranged for plug connection to a circuit board by movement parallel to the board surface and providing electrical shielding for the circuit.

Broad-band signal transmitting device using transformer

Abstract: A broad-band signal transmitting device including a signal transmitting transformer of the primary to secondary turn ratio 1 : N, comprising a first circuit for expanding the transmission band to low frequencies by decreasing the impedance as well as by decreasing the gain for the signal component in the primary circuit of the transmission transformer, a second circuit connected with the output side of the transmission transformer having an impedance larger than N 2 times of the impedance of the primary side and smaller than the impedance exhibited by the stray capacitance of the secondary side at the upper limit of the transmission band, an amplifier for recovering the gain drop in the first circuit, and a low frequency compensating circuit for compensating the lack of low frequency transmission characteristic due to the transmission transformer

A useful modification of the technique for measuring capacitance as a function of voltage

Abstract: Measurements of small signal capacitance as a function of applied bias voltage are widely used for the determination of information about metal-insulator-semiconductor (MIS) capacitors. The information that can be derived from the measurements includes interface-state density and flat-band charge density at the insulator-semiconductor (IS) interface, semiconductor doping, and charge stability under bias-temperature stress. A limitation on the use of this measurement method which has until now prevented its even more general application is the requirement that in order to determine C s , the semiconductor space-charge capacitance, with reasonable accuracy the ratio of C s to C I , the insulating layer capacitance, must be ∼ 10. In the present work it is shown that a modification of the usual method can significantly relax this restriction and allow the accurate determination of C s when the ratio C s /C r is as large as 100 or more, In fact, the inherent limit is no longer directly dependent on this ratio but on the noise level in the capacitance measurement. In some cases C s /C I ≥ 1 due to a thick insulating layer, A very large bias voltage is then required to span the capacitance range of interest; commercially available capacitance meters which typically have applied bias capabilities of ±600 V or less may be inadequate. A simple circuit modification has been employed to allow much larger bias voltages (up to ± 7 kV in the present Work) to be applied to the sample without alteration of or damage to the capacitance meter.

Diode controlled idle current injection

Abstract: Diodes having a fast response time are used in an Emitter-Coupled Logic (ECL) current switch circuit to cause the injection of an idle current in each of the transistors of said switch. The injection of the idle current through these transistors causes them to operate at all times in an active region. When the transistors remain in the active operating region and are subjected to a switching transient, the parasitic capacitance associated with emitter base and collector base junctions are not charged and discharged to the same extent that they would be if the transistor was turned off completely. Moreover, if the transistors are held on, delay required for minority profile "buildup" in the base region is reduced and the current switch's propagation delay is reduced. When the fast response diodes are used to cause the injection of idle current in a cascode circuit, the overall transient response is greatly improved in both the lower and upper current switch sections; and there is a reduction of spurious output signals. Schottky diodes can be used in said circuit due to their fast response time. Alternatively large value resistors or current source transistors are used when diodes are not used.

System for transferring charge between spaced apart CCDs by direct series connection

Abstract: Charge is transferred from the output of one charge coupled device (CCD) to the input of another through a direct connection by means of special DC biased coupling electrodes in each. The effect of the inter-CCD conductors'' stray capacitance is minimized by the relatively large dynamic input resistance introduced into the receiving CCD by its coupling electrode.

Multiple flash lamp unit

Abstract: A multiple flash lamp unit having a group of electrical connector terminals connected via circuitry to lamps in the unit in a manner so that one terminal and its associated circuitry has relatively more stray capacitance to ground than any of the other terminals and their circuitry. This one terminal is shaped and arranged to be more readily touched than the other terminals when the unit is handled, thus reducing the likelihood of lamps being accidentally flashed by electrostatic charges. Preferably, a large-area shield member is connected to the more readily touchable terminal to increase its stray capacitance to ground.

The JFET as a photosensitive cell in image sensor arrays

Abstract: JFETs, as photosensitive elements, offer gain and non-destructive readout; additionally switching transients and attenuation by parasitic capacitances can be eliminated. A 5 × 5 array, using a double punch-through a resetting method, will be described.

Minority carrier lifetime measurement in GaAs

Abstract: A technique for the determination of relatively short carrier lifetimes (< 1 ns) is presented. By measuring the frequency dependence of the diffusion capacitance of a one-sided abrupt-junction GaAs diode, the minority carrier lifetime can be obtained. The method has the advantages that it is repeatable after exposing the diode to further processing, the diode can be mounted in a convenient package so that no special handling precautions are necessary, and the method can be automated.

Low-Cost X-Band MIC Parametric Amplifier

Abstract: An X-band MIC parametric amplifier using planar printed circuit techniques which result in low-cost and high reliability has been developed. Design of a microstrip four-port circulator and parametric amplifier stage on a low-loss YIG substrate, a 31-GHz microstrip pump source on teflon-fiber glass, and a pump source at the same frequency in integrated fin-line are described.

Method and apparatus for reducing noise in pam time division networks

Abstract: In pulse amplitude modulated time division switching systems, noise and crosstalk often result because the time division switches used to connect individual channels to a common bus are not perfect open circuits when they are in the off-state. The switches in the off-state possess a small parasitic capacitance which couples energy on the common bus to the channel resulting in a noise signal during time slots which are not associated with the channel. A method is disclosed for substantially reducing crosstalk and noise induced by stray capacitances without increasing the complexity of the time division switch. Each pulse on the common bus is converted into a bipolar pulse in which positive and negative portions have equal average values. In addition, the timing of each of the time division switches is modified to extract the desired signal by sampling the first portion of the bipolar pulse in the appropriate time slot for that channel, and rejecting the second portion of the bipolar pulse. The noise energy which is coupled from the common bus to the channel by stray switch capacitance during other time slots remains essentially bipolar in form and tends to cancel itself. The noise power at low frequencies is therefore substantially reduced. Apparatus is also disclosed for converting pulses on the common bus into the bipolar format required by the invention.

AFC circuit with improved sensitivity

Abstract: An AFC circuit has a tuning circuit including a first variable capacitance element and a pair of series connected inductive elements. Switch means are connected between ground and a point between the inductive elements for alternatively operably connecting one or both of the inductive elements in parallel with the first variable capacitance element to switch the tuning circuit between a higher frequency range and a lower frequency range. The AFC portion of the circuit comprises a second variable capacitance element which is connected in parallel with the first variable capacitance element. In order to improve the sensitivity of this circuit, a means is provided for capacitively coupling the second variable capacitance element to a point between the inductive elements. As a result, substantially equal AFC ranges are obtained whether the circuit is tuned to the higher or the lower frequency range.

Design of Optimum Acoustic Surface Wave Delay Lines at Microwave Frequencies (Short Papers)

Abstract: Optimum procedures for designing microwave acoustic surface wave delay lines are given. Combined beam steering fraction loss curves are provided as a function of the basic material parameter, the slope of the power flow angle, to allow optimum choice of material for a given application. Methods for designing uniform periodic interdigital transducers including finger ohmic loss, lossy tuning elements, and parasitic capacitance have been extended to account for beam steering and diffraction.

A study on dynamic design and applications of a tunnel-diode-transistor combined circuit

Abstract: The dynamic design of the tunnel-diode-transistor combined circuit, in which a tunnel diode is connected in parallel with the collector junction of a transistor, is discussed. A monostable circuit, a frequency divider and a ring counter are shown as circuit examples.

Time-Sharing High Frequency Inverter Circuit

Abstract: To overcome the limitations of the SCR turn-off time, time-sharing principle is utilized in high frequency bridge inverters. Such an inverter circuit is analyzed. Triggering frequency requirements are discussed. Criterion for the choice of series compensating capacitor is presented. In addition, a number of nomograms are presented and their use in the circuit design is discussed.

Gas discharge panel information read-out system

Abstract: A system for reading out information in a plasma display memory panel having a set of X and a set of Y electrodes is disclosed in which a forward current is conducted through unidirectional conducting devices having a charge storage effect, for example, charge storage diodes, connected to the X or Y electrodes; a read voltage is applied to one of a selected one of the Y sets of and X electrodes; a charging current due to the read voltage is conducted through the charge storage diodes in a backward direction making use of their backward recovery time; a gas discharge current, after the charging current terminates, flows in the stray capacitance of the selected X or Y electrode, raising its potential relative to the ground potential; and the potential rise is detected to thereby effect read-out of the information.

The effect of package parasitics on a series connected GaAs IMPATT diode

Abstract: Computer analysis of a series connected GaAs IMPATT diode is presented. Very good agreement between theoretical appraisal and the experimental observations is obtained. A better thermal dissipation and a smaller parasitic capacitance are the solution to the key problem areas for the series connected device.

A New Concept for Microstrip-Integrated GaAs Schottky-Diodes

Abstract: A new concept for integrated planar Schottky-diodes has been developed. It meets the two important requirements in the design of microwave diodes: high cutoff frequency and low parasitics. Only one epitaxial layer is needed. The Schottky contact is deposited on the slope of a mesa in order to obtain both low series resistance and low capacitance. Up to now a zero bias cutoff frequency of 150 GHz has been achieved. The advantage of this type of diodes as compared to planar diodes produced by double selective epitaxy is the use of standard technology, resulting in good reproducibility and yield.

The large signal input capacitance of a transistor amplifier

Abstract: A simple bipolar transistor amplifier generates subharmonics at frequencies well below f/SUB /spl beta//. A study of the results of a computer-aided design program reveals that a large nonlinear capacitance appears at the transistor input. The source of the nonlinear capacitance is found.