AMPLIFIER, AMPLIFYING METHOD AND FILTER

摘要

An amplifier is provided with a first variable capacitance element whose capacitance varies; a second variable capacitance element, which is electrically connected to the first variable capacitance element and has a conductivity opposite to that of the first variable capacitance element; and a first input section for selectively inputting bias voltages and voltage signals to the first variable capacitance element and the second variable capacitance element. In the case of inputting bias voltages and the voltage signals to the first variable capacitance element and the second variable capacitance element, the capacitance of the first variable capacitance element and the second variable capacitance element is set at a first value, the capacitance of the first variable capacitance element and that of the second variable capacitance element are set at a second value, which is smaller than the first value, and the voltage signal is amplified.