Patent ID: 8278975

Claim:
A sinusoidal waveform generation circuit for generating a sinusoidal waveform based on a waveform generation command inputted from an external side, the sinusoidal waveform generation circuit comprising: a MOSFET having a gate, a drain and a source and producing an output current from the drain to the source when a voltage is applied to the gate; a gate voltage application section for applying the voltage to the gate of the MOSFET when the sinusoidal waveform generation command is inputted; and a capacitor having a first end connected to the gate and a second end connected to the source of the MOSFET so that the voltage applied to the gate of the MOSFET is changed approximately in a sinusoidal waveform; wherein the voltage application section is configured to change the output current in a form of a sinusoidal wave by continuously applying the voltage to the gate of the MOSFET based on an electric characteristic between a gate voltage and an output current in a MOSFET; and wherein the first end of the capacitor is connected directly to the gate of the MOSFET.