| 摘要 |
PROBLEM TO BE SOLVED: To provide an electronic variable resistor circuit which can be driven by a single power source and therefore constituted as an LSI with an oxide film for the signal power source and a junction process. SOLUTION: An operational amplifier 29 attenuates the amplitude of a (+) and (-) bipolar input signals applied to an input terminal 1 and also converts it into a unipolar (+) signal. A variable resistance circuit 25 controls the attenuation degree of the operational amplifier 29, according to a signal which is supplied from the outside. An operational amplifier 43 amplifies the output signal of the operational amplifier 29 and converts the resultant signal into a bipolar signal.
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