Pioneer Electronic Corporation

Tohru Kageyama

Takashi Yamaguchi

Hiroo Adachi

Shinichi Ogura

Tetsuya Watanabe

Keiichi Ogawa

Osamu Shishido

Yoichi Nishiyama

Yuuichi Mineo

This invention provides a volume apparatus, which is formed of semiconductor resistors and semiconductor switches and which reduces distortion and noise in attenuation signals. The volume apparatus, which comprises: a first semiconductor voltage dividing circuit successively attenuating an input signal and outputting attenuated signals; a first semiconductor switch circuit controlling the supply of the attenuated signals output from the first semiconductor voltage dividing circuit; a phase inversion circuit for inverting the phase of the input signal; a second semiconductor voltage dividing circuit successively attenuating the input signal output from the phase inversion circuit and outputting attenuated signals; a second semiconductor switch circuit controlling the supply of the attenuated signals output from the second semiconductor voltage dividing circuit; a volume control circuit controlling the first and second semiconductor switch circuits according to a control signal; and a differential amplifier having one of input terminals thereof connected to the output of the first semiconductor switch circuit and the other connected to the output of the second semiconductor switch circuit.

Volume control apparatus producing reduced noise and distortion

A heat sink/circuit board assembly allows repairing or inspection of circuit or parts without impairing heat-radiating effect. A sub-heat sink is protruded from a lateral end of the circuit board in a direction parallel to the main surface of the circuit board and is connected to the main heat sink at its protruding portion. The diameter of the opening of the recessed portion of the main heat sink facing the circuit board is made larger than outer diameter of the circuit board. When circuit elements on the main surface of the circuit board facing the recessed portion of the main heat sink are to be repaired or inspected, the main heat sink is connected to the sub-heat sink on a main surface which is on the opposite side to the surface carrying the circuit elements, while the same heat-radiating effect as in the normal condition can be obtained.

Heat sink/circuit board assembly

Growing community of inventors

Kawagoe, Japan

Tohru Kageyama