Matching circuit, semiconductor device, and electronic device

An impedance-matching circuit comprising:

• a first input terminal configured to input an alternating-current signal;
• a second input terminal configured to input a constant potential;
• an output terminal;
• a transistor comprising a first gate, a second gate, a source and a drain;
• and
• an inductor comprising a first terminal and a second terminal,
• wherein one of the source and the drain is electrically connected to the first input terminal,
• wherein the first gate of the transistor is electrically connected to the first terminal of the inductor,
• wherein the output terminal is electrically connected to the second terminal of the inductor,
• wherein the second terminal of the inductor is configured to input a first constant potential,
• wherein the transistor comprises an oxide semiconductor, and
• wherein the second input terminal is configured to change the constant potential from the first constant potential into a second constant potential.