JPS62152512U

JPS62152512U -

Info

Publication number: JPS62152512U
Application number: JP3980686U
Authority: JP
Priority date: 1986-03-20
Filing date: 1986-03-20
Publication date: 1987-09-28

Description

[Brief explanation of drawings]

第１図は本考案のレベル調整回路の一実施例を
示す回路図、第２図は第１図のレベル調整用可変
抵抗の抵抗変化特性を示す特性図、第３図は第１
図の回路における音量コントロール特性を示す特
性図、第４図は従来のレベル調整回路を示す回路
図、第５図は従来回路における可変抵抗値の変化
に対する出力レベルの変化特性を示す特性図であ
る。１２，１４……トランジスタ、１３，１５，１
６，１７，１９……抵抗、１８……可変抵抗。 FIG. 1 is a circuit diagram showing an embodiment of the level adjustment circuit of the present invention, FIG. 2 is a characteristic diagram showing the resistance change characteristics of the level adjustment variable resistor shown in FIG. 1, and FIG.
FIG. 4 is a circuit diagram showing the conventional level adjustment circuit; FIG. 5 is a characteristic diagram showing the change characteristics of the output level with respect to changes in the variable resistance value in the conventional circuit. . 12, 14...transistor, 13, 15, 1
6, 17, 19...resistance, 18...variable resistance.

Claims

[Claims for Utility Model Registration] It has first and second transistors forming a differential pair, and a DC voltage for output level adjustment is supplied to the bases of these transistors via a resistor, so that each a differential amplifier that adjusts the voltage difference between the bases, amplifies the input signal applied to the common emitter side according to the change in the DC voltage, and outputs the level-adjusted signal from the collector of one transistor; third and fourth transistors whose collector-emitter paths are connected in series between the base of the dynamic amplifier and the reference potential point; a voltage divider circuit connected between the voltage source and the reference potential point; , a variable resistor whose both ends are connected between the voltage source and the reference potential point, and whose sliding end is connected to the voltage dividing point of the voltage dividing circuit, the mechanical midpoint of both ends of the resistor and the reference potential point a variable resistor having a linear characteristic in which a resistance change characteristic between the voltage source and the mechanical midpoint rises in a straight line, and a curved resistance change characteristic in which a resistance change characteristic between the voltage source and the mechanical midpoint rises steeply; means for supplying the variable voltage obtained by sliding the sliding end of the variable resistor to the base of the third transistor; 1. A level adjustment circuit comprising means for supplying a voltage to the base of a fourth transistor and changing the fourth transistor from conductive to non-conductive when the changing voltage reaches a predetermined level.