Abstract: An improved transimpedance amplifier includes a common cathode-connected vacuum tube first stage, coupled to a common-drain-connected MOSFET second stage, and an optional common drain-connected MOSFET third stage. Preferably, capacitive feedback is coupled from the output of the second stage to the input of the vacuum tube stage, to control the transimpedance of the amplifier. The circuit takes advantages of the low stray inter-electrode capacitances, low delay and transit times of the vacuum tube and the high transconductance of the MOSFET second and optional third stages, in a way complementary to one another to form a high transimpedance amplifier whose characteristics are controlled almost exclusively by the feedback capacitance or other feedback impedance, rather than by gain and stray capacitance terms of individual devices. The resulting transimpedance amplifier is useful in a number of applications, for example, in audio preamplifiers and audio power amplifiers.

Abstract: A stabilized Cascode Amplifier Circuit wherein the grid or gate control of the second stage of the cascaded input is provided by feedback of a portion of the output signal voltage. The circuit can be further enhanced by the inclusion of a unity gain follower between the first and third stage of the cascode amplifier circuit.

Abstract: The technical field to which this invention pertains is high-voltage amplifiers. The amplifier includes a high-voltage capacitor (C1) across which the output of the amplifier is developed. This capacitor is charged towards the supply potential (V) by a constant current generator (10). At the same time, the capacitor is continuously discharged by a controllable current generator (11). A voltage amplifier (13) connected to the input signal to be amplified and to a scaled-down version (R,R) of the output of the high-voltage amplifier, alters the rate at which the capacitor is discharged and, hence, the output voltage developed across the capacitor. The principal use of the invention is to drive the electrostatic deflection plates of an ion implantation machine or an electron beam milling apparatus. The invention may also be used to drive other highly capacitive loads, for example, piezo-electric crystal devices.

Abstract: Signal currents corresponding to a voltage to be converted into current or to a current to be amplified are applied to one input of an operational amplifier and its other input is referenced to ground. Its output is connected via a power amplifier and a small resistance to an output terminal and means are provided for supplying current proportional to the voltage across the resistance to the signal input of the operational amplifier with such polarity as to tend to cancel the signal current present thereat.

Abstract: A wide bandwidth, low power dissipation, cascode video output amplifier suitable for driving an in-line gun color picture tube or the like. The cascode amplifier includes a low voltage, small signal, common emitter amplifier transistor and a high voltage common base transistor. An active load circuit comprising a transistor of like conductivity with respect to the common base and common emitter transistors is coupled between the collector of the common base stage and a source of operating voltage. A disconnect diode, interposed between the emitter of the load transistor and the collector of the common base transistor, is based to a non-conductive state under quiescent conditions. Voltage dependent current feedback is provided from the emitter of the load transistor to the base of the common emitter transistor. Operating current for the cascode arrangement is provided via a resistor coupled from the operating voltage source to the base of the load transistor and the collector of the common base transistor.

Abstract: A fully passive frequency contouring amplifier using segregated passive networks to shape the different portions of the signal thus avoiding all phase distortion and permitting the stages to be coupled without coupling capacitors, thus avoiding distortion caused by the nonlinearities of capacitors. In addition, a special DC servo loop is used to drastically reduce DC amplification.

Abstract: Automatic gain control is provided in a two stage amplifier in which the first stage has a signal voltage gain related to its supply voltage and the second, or output, stage comprises an output transistor. The load of the output stage comprises an earphone in series with the supply. The supply for the first stage is taken from the junction of the output transistor and the earphone such that the gain varies inversely with the output of the earphone. The amplifier stages may be formed as a monolithic integrated circuit and contained in the housing of the earphone.