| 摘要 |
PURPOSE:To obtain a stable converter which is not influenced by a variation of a temperature or a distributed capacity of a voltage, etc., without using the constitution of a bidirectional constant-current circuit using a semiconductor. CONSTITUTION:Between a non-inversion input terminal (+) of an operational amplifier Q3 and an output terminal, resistances R3, R4 are connected, and to its inversion input terminal (-), a constant voltage V0 and a voltage which has been divided by resistances R5, R6 are impressed. Also, an output terminal of the amplifier Q3 is connected to an input terminal of an inverter G3, its output terminal is connected to a connecting point of the resistances R3, R4 through a resistance R7, and also it is connected to one end of a variable capacity C1 through an inverter G4. Also, the other end of the capacity C1 is connected to a common potential point COM through an electrostatic capacity C2, and also connected to the non-inversion input terminal (+) of the amplifier Q3. In this regard, a distributed capacity CS of both ends of the capacity C1 is compensated by a compensation capacity CCP' which has been connected to both ends of the resistance R4, therefore, it is not influenced by a junction capacity of a semiconductor element as in the past.
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