Amplification circuit

An amplification circuit comprising:

• a semiconductor amplification element;
• a current feedback circuit connected to a terminal close to a ground side of the semiconductor amplification element and can control gain reduction;
• and
• a voltage feedback circuit connected between an input terminal and an output terminal of the semiconductor amplification element and can control feedback voltage,
• wherein the feedback voltage of the voltage feedback circuit varies according to the gain reduction controlled by the current feedback circuit,
• wherein the feedback voltage of the voltage feedback circuit is increased as the gain reduction controlled by the current feedback circuit is increased,
• wherein the feedback voltage of the voltage feedback circuit is decreased as the gain reduction controlled by the current feedback circuit is decreased,
• wherein the current feedback circuit has a first resistance portion with a variable resistance value, and controls the gain reduction according to the resistance value of the first resistance portion,
• wherein the voltage feedback circuit has a second resistance portion with a variable resistance value and controls the feedback voltage according to the resistance value of the second resistance portion,
• wherein the resistance value of the second resistance portion is decreased when the resistance value of the first resistance portion is increased, and
• wherein the resistance value of the second resistance portion is increased when the resistance value of the first resistance portion is decreased.