Cross Technology, Inc.

Threepenny Electronics Corporation

Argosy Electronics, Inc.

Threepenney Electronics Corporation

William A Johnson

David A Preves

An amplifying system for variably amplifying electrical input signals, depending on magnitudes of those signals, with the variation in amplification being selectable as is substantially the maximum output signal value.

Variable gain amplifier

A current drain reducer for an electronic circuit system such as an electronic amplifier operated through controlling selected circuit branches therein in response to sensing a selected position of a potentiometer used therein. Such circuit branches each has a control conductivity device located therein which has a control therefore connected to a shutdown signal generator which can be a power supply. The potentiometer can have its low terminals in one such circuit branch which may be in a first electronic amplifier circuit and its wiper connected to another such circuit branch which may be in a second electronic amplifier. A sensing circuit for sensing the position of the wiper provides an output signal to the shutdown signal generator.

Battery drain reducer

An output amplifier having a pair of controlled current generators each with an output impedance that is electrically connected to the other, a pair of output controllers each of which is across a corresponding one of the output impedances, and a pair of feedback impedances each connected from a corresponding one of the output controllers to a corresponding one of the controlled current generators. A differential amplifier is provided ahead of the controlled current generators with the amlifier input capacitively connected to the input of such differential amplifier. An offset adjuster is provided between the output impedances having its output connected to the capacitively connected differential amplifier input. A current feedback arrangement is provided between the output impedances and connected to the controlled current generators to be capable of altering currents generated thereby.

Output amplifier

A signal processing circuit for hearing aids includes a broadband peak detector for generating a control voltage based upon the sound pressure level of an incoming acoustical signal over its entire frequency spectrum. The control signal is used to determine the cut-off frequency of a voltage controlled adaptive high-pass filter. An amplified electrical signal, corresponding to the acoustical signal, also is provided to the high-pass filter. In setting the cut-off frequency, the control voltage causes the high-pass filter to selectively suppress the low frequency portion of the signal, generating a modified signal in which the noise component is reduced.

Frequency selection circuit for hearing aids

An amplifier system having an input active device at its first input and having its second input provided through an inverting means to that first input.

Asymmetrical dual input amplifier

An amplifier system providing the voltage feedback which can be supplemented with current feedback without limiting the voltage excursion range at the amplifier system output.

A voltage regulator having a series regulator operated by a shunt regulator.

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Minneapolis, MN, United States of America

William A Johnson