Showing papers on "FET amplifier published in 1969"

Time-shared instantaneous gain-ranging amplifier

Abstract: One-hundred low-frequency analog signal channels having a very large dynamic range, may be amplified to at least half of full scale a 14 bit analog to digital converter without distortion by an amplifier system that includes an instantaneous gain-ranger, a preamplifier for each channel, a filter system for each channel, a premultiplexer gain-ranging amplifier for each channel, and a multiplexer. The instantaneous gain-ranger consists of a series of binary amplifier stages, threshold detecting circuitry and logic circuitry. The output is taken from the first unsaturated amplifier. The preamplified and premultiplexer gain-ranging amplifier are connected into the system ahead of the multiplexer and provide a sufficient signal-to-noise ratio to mask the noise introduced into the system by the multiplexer. The output of the system is typically digitized.

Biological electrode amplifier

Abstract: An apparatus is disclosed comprising an electrode for detection of biopotentials, and a high-input impedance, low-noise amplifier packaged with and in direct contact with the electrode, the input terminal of the first active device of the amplifier being epoxy bonded to the electrode. The amplifier is designed with thick film resistors, and without any capacitors, thus minimizing noise generation in the amplifier.

Sound-responsive light

Abstract: A sound-responsive light illuminated by an audio-actuated serially connected switch. The audio-actuated switch includes a thyristor, preferably an SCR, the gate of which is triggered by an audio frequency signal from a microphone and audio amplifier. The amplifier is a class A audio amplifier with biasing and loading provided so that the light will be illuminated by sound above a selected level. A nonlinear potentiometer is used for the load impedance of one of the amplifier stages to permit selection of the desired audio level which triggers the thyristor. The input terminals of a rectified power supply are connected across the principal terminals of the SCR so that the parallel combination may be connected in series with the electric light and an alternating current power source. Coupling is provided from the output of the audio amplifier to the gate of the thyristor by means of a series capacitor and a shunt gate resistor of approximately 1000 ohms.

Amplifier circuit providing a floating output

Abstract: AS AN ALTERNATIVE TO A TRANSFORMER AS A MEANS FOR PROVIDING A FLOATING OUTPUT THE INVENTION USES TWO CROSSCOUPLED DIFFERENTIAL AMPLIFIERS IN A NOVEL CIRCUIT CONFIGURATION. THE CIRCUIT IS MUCH LESS BULKY THAN A TRANSFORMER AND CAN BE MICRO-MINIATURIZED.

Electronic control system for shaping the fuel-speed characteristics of an internal combustion engine

Abstract: Additional amplifiers are connected in parallel to the high gain direct current amplifier of the parent application. These have a very high output impedance compared to the output impedance of the direct current amplifier. All amplifier outputs are connected to a voltage divider tap from which the fuel control signal is derived. The additional amplifiers have inherent temperature compensation and shape the full-load limiting line, while the original high gain direct current amplifier shapes the speed control lines.

Regenerative fet source follower

Abstract: This specification describes a logic circuit having a capacitor coupled between the gate and source of an FET to cause the potential at the gate to follow the potential at source. The charge of this capacitor is controlled to render the FET conductive or nonconductive so that pulses applied to the drain of the FET can be selectively gated or not gated through the FET to a load connected to the source of the FET. By operating the FET in this way small supply voltages may be used. These voltages can be in the order of the size of the signals transmitted to the load.

Hall-effect amplifying device with temperature compensated characteristic

Abstract: A Hall-effect amplifying device comprising a Hall generator and an electronic amplifier is provided with a feedback resistor circuit which connects the amplifier output directly with one of the two Hall-voltage electrodes of the Hall generator. The amplifier in this device is an electronic direct-current amplifier of high-ohmic input resistance and high no-load gain. The resistance of the feedback connection is two or more orders of magnitude higher than the internal resistance between the Hall-voltage electrodes of the Hall generator.

Bias networks for class b operation of an amplifier

Abstract: A means for baising a complementary Class B transistor amplifier which has the capability of maintaining the amplifier at a minimum distortion operating point over large ambient temperature variations.

High-dynamic-range amplifier

Abstract: An amplifier for amplifying radiofrequency signals having a lownoise figure and the ability to handle relatively large amounts of power with low distortion. The high-dynamic-range amplifier comprises a dual directional coupler, having two ports coupled to the signal source and load and two ports coupled to an inverting amplifier, in which the input and output impedances of the amplifier are equal and are equal to the characteristic impedance of the source and load.

Precision rectifier with fet switching means

Abstract: A PRECISION FULL-WAVE RECTIFIER USES A SINGLE OPERATIONAL AMPLIFIER WHICH IS OPERATED SIMULTANEOUSLY AS A LINEAR AMPLIFIER AND A SWITCH DRIVER. A PAIR OF FETS ARE UTILIZED AS VOLTAGE RESPONSIVE SWITCHES FOR EFFECTING THE RECTIFYING OPERATION AND ARE GATED IN RESPONSE TO THE OUTPUT OF THE OPERATIONAL AMPLIFIER.

Circuit for reducing switching transients in fet operated gates

Abstract: An FET analog gate includes two equal-valued resistors, one in the source path and one in the drain path of the FET, and a differential amplifier, one input connected to the FET source terminal and the other input connected to the FET drain terminal.

Current amplifier and inverting circuits

Abstract: CURRENT AMPLIFIER AND CURRENT INVERTING CIRCUITS ARE DESCRIBED WHICH ARE COMPRISED OF SEMI-CONDUCTOR ELEMENTS AND WHICH OPERATE IN THE CURRENT DOMAIN.

Random noise generator diode with impedance matched transistor amplifier

Abstract: A random noise generator employs a silicon diode as the active noise source in an amplifier circuit where the output impedance of the noise diode is matched to the input impedance of the amplifier circuit to provide an increased frequency spectrum, temperature stability and increased independence of power supply variations

Fet differential amplifier

Abstract: A differential amplifier for use with electrometers. The input stage employs unmatched field effect transistors for high-input impedance. The circuit is arranged for compensation and adjustment to provide satisfactory operation with unmatched transistors.

High-gain differential amplifier

Abstract: A high-gain, linear, differential amplifier which provides output voltage variations substantially equal to the total supply voltage associated with the amplifier. Each half of the amplifier comprises an input transistor, a shunt regulator transistor and a feedback arrangement between input and regulator transistors to maintain substantially constant current in the input transistor. Output transistors having their inputs in parallel with the regulator transistor inputs and output loads coupled in their collector-emitter current paths are provided.

Bias control circuit for semiconductor amplifier

Abstract: AN OTL TYPE AMPLIFIER OF COMPLEMENTARY OR QUASICOMPLEMENTARY TRANSISTOR STRUCTURE HAS CONNECTED BETWEEN A VOLTAGE SOURCE AND AN OUTPUT OF ONE OF THE OUTPUT TRANSISTOR A PARALLEL ARRANGEMENT OF DIODE AND RESISTOR TO DETECT A CURRENT FLOWING THROUGH THE TRANSISTOR. THE DETECTED CURRENT PASSES THROUGH A LOW-PASS FILTER AND AFTER AMPLIFICATION IT IS APPLIED TO A BASE OF A CONTROL TRANSISTOR. A VOLTAGE ACROSS ITS EMITTER AND COLLECTOR CONTROLS THE AMPLIFIER TO BE PUT IN THE CLASS B OR AB OPERATION.

Amplifier system for driving shaker motors

Abstract: A modular bridge-type solid-state amplifier capable of delivering several kilowatts of audiofrequency power over a frequency range of zero to approximately 7,500 Hertz and which has an output impedance selectively variable from substantially zero to approximately 100,000 ohms. The amplifier employs both positive and negative feedback, with the selected output impedance being obtained by varying the amount of signal feedback to the preamplifier from the output terminals and an output current sensor. The amplifier may readily be expanded to obtain either voltage or current gain, or both, by adding appropriate modules in series and parallel arrangements, or combinations thereof.

Analog data transmission system

Abstract: A multiplicity of remote analog signal-transmitting devices which time share a direct-current analog bus each include electronic switching within a feedback amplifier loop so that loop gain removes error due to switch voltage drop. Operation of the electronic switching when a given amplifier is not controlling the bus isolates the amplifier terminal connected to the bus from any power supply or signal voltages of the amplifier and allows the amplifier to present a high impedance load to any other signal-transmitting device then controlling the bus.

Connection arrangement for a telephone microphone amplifier with power supply connected to the output side of the amplifier

Abstract: A speech amplifier for telephone microphones including an input direct coupled, differential amplifier, and an output Darlingtonconnected amplifier, with the operating points stabilized by forward-biased diodes.

Resonant network with reactively coupled fet providing linear voltage/frequency response

Abstract: A field-effect transistor with two gates has a resistance and a reactance serially connected across its drain and source, with one gate tied to the junction of these two impedances whereas the other gate has a modulating signal applied to it. The resistance may be constituted by the output circuit of a differential transistor amplifier having its input connected in parallel with drain and source of the field-effect transistor.

A 4-GHz Multistage Transistor Amplifier

Abstract: Multistage microwave transistor amplifiers of simple construction have been developed. In these amplifiers, unit amplifiers of the same design are connected in cascade with short transmission lines inserted between each amplifier. The n-stage (three-, four-, five-, six-, and seven-stage) amplifiers designed for the 4-GHz band gave power gains n times that of the unit amplifier (4 dB) and flat bandwidths of about 1000 MHz. The stripline circuit of the amplifier is fabricated on alumina substrates in the usual way. The amplifier has the disadvantage of poor input and output impedance matching. However, this problem was solved by integrating isolators in the input and output ports of the multistage amplifier. Noise performance of the amplifier is also described.

Logarithmic if amplifier

Abstract: The logarithmic IF amplifier disclosed herein is a synchronously tuned multi-stage cascaded transistor amplifier. Each amplifier stage includes an emitter follower and is loaded with modified complementary filter. This type of loading ensures a substantially purely resistive IF load driving point impedance and prevents change of the logarithmic characteristic at high input signal levels. The present invention also comprehends the use of series resistors in the base bias network to compensate for changes in gain resulting from decreased collector voltage during conditions of high signal level.

Distributed amplifier damping circuits

Abstract: In a distributed amplifier adapted to amplify a bandwidth of signals having lower and upper band edge frequencies a parallel R-L-C circuit adapted for antiresonance at the upper band edge frequency is provided in series with at least one of the inductors in the series branches of the grid and plate transmission lines of the amplifier to provide stability to the amplifier. Additionally, another parallel R-L-C circuit adapted for antiresonance at the lower band edge frequency is provided in series with at least one of the inductors in the shunt branches of the amplifier grid and plate transmission lines to also provide increased stability to the amplifier.

Stacked differential amplifiers

Abstract: A cascaded train of transistor differential amplifier circuits are operated with a single primary constant current source connected to the first amplifier of the train. The constant current sources for each of the other differential amplifiers are obtained by recombining the signals present on the collectors of the transistors in the next preceding amplifier in common to the emitters of each of the transistors in the subsequent differential amplifier stage.

Bipolar voltage amplifier

Abstract: A BIPOLAR VOLTAGE AMPLIFIER HAVING A RELATIVELY HIGH OUTPUT VOLTAGE AND A RELATIVELY HIGH SLEWING RATE INPUT SIGNALS ARE APPLIED TO THE EMITTERS OF A PAIR OF SERIALLYCONNECTED COMPLEMENTARY TRANSISTORS IN COMMON-EMITTER CONFIGURATION THE AMPLIFIED SIGNALS DEVELOPED ACROSS THE COLLECTORS OF THE FIRST PAIR OF TRANSISTORS ARE FED TO THE EMITTERS OF A SECOND PAIR OF COMPLEMENTARY TRANSISTORS CONNECTED IN PUSH-PULL, COMMON-BASE CONFIGURATION

High-efficiency vhf power amplifier.

Abstract: : The report describes a high-efficiency broadband RF Power amplifier with collector efficiencies as high as 80% at 40 W output in the frequency range from 30 to 76 MHz. The amplifier was designed to fit the RT-524 radio set. The design and testing of the amplifier and associated protection circuitry is discussed. The report also explains the advantage found in using such an amplifier rather than conventional type amplifiers. (Author)

Circuit for measuring variable timing intervals

Abstract: This timing circuit includes a first FET which is normally conducting in the absence of a starting signal and is in shunt with a timing capacitor. The timing capacitor is in series with a resistor and their junction is connected to the first FET and to the gate of a second FET. The second FET has its source biased at a voltage determined by the setting on a timing dial potentiometer. It will not conduct until the charge built up on the timing capacitor, after the first FET turns off, exceeds the bias and the inherent pinch-off voltage of the second FET. When the second FET conducts, a voltage is developed across another resistor which is applied to turn on a transistor that is in series with a resistor. When the transistor turns on, the voltage across the latter resistor turns on two other transistors in series with an inductor. Energization of the inductor actuates a switch associated with the load circuit which is to be controlled. A diode is connected between the second FET and the series-connected transistors to keep the second FET conductive despite an increase in the setting of the dial potentiometer after completion of the timing cycle, but before the starting circuit is deengerized.