Sony Corporation

Toshihiko Miyata

Takashi Shibata

An indicator and display for use with a graphic equalizer which receives an audio signal and includes first and second band pass filters which receive the audio signal and pass different pass bands, first and second variable resistors which have control shafts and knobs connected thereto with illuminators mounted in the knobs, first and second rectifiers connected to the output of the band pass filters, and first and second drive circuits connected to the outputs of the first and second rectifiers and the drive circuits connected to the illuminators in the knobs and an oscillator switching circuit connected to the illuminators so as to cause the illuminators to flash under certain conditions.

Frequency response display for use with a graphic equalizer

An amplifier having at least a drive stage and an output stage, the output stage comprised of an FET for applying an amplified signal to a load. The drive stage includes a transistor device whose output is direct coupled to the gate electrode of the FET, the transistor device being supplied with an input signal to be amplified. A constant current source is coupled to the output of the transistor device, and thus to the gate electrode of the FET, and provides a current of predetermined magnitude to thus limit the gate leakage current during periods that the FET is cut off.

Amplifier with FET having gate leakage current limitation

A load protective circuit having a class B amplifying stage driven by a class A amplifier and a load DC coupled to the class B stage, in which means are provided for detecting an undesirable DC voltage at the output of the class B amplifying stage and for producing a control signal in response to the output of the detecting means. A first protective means shunts the input signal to the class B amplifier to ground in response to the control signal. A second protective means controls a switching means connected between the output point and ground so as to connect the output point of the class B amplifier to ground in response to the control signal to thereby remove any undesirable DC voltage from the output point of the amplifier and to protect the DC coupled load from being damaged.

Growing community of inventors

Tokyo, Japan

Toshihiko Miyata