Method for forming an electric signal representing a sound and a device therefor

A method for driving a field effect transistor for forming an electric input signal, representing a sound, to an output signal, which method comprises modifying the input signal to an intermediate signal, and output of said intermediate signal to the field effect transistor for forming the output signal, characterized by the steps of:

• setting the quiescent point of the field effect transistor such that the same is placed in the quadratic region of a transfer characteristic of the field effect transistor by adjusting the potential between a gate terminal and a source terminal of the field effect transistor by means of the direct-current voltage level of the intermediate signal and the potential of the source terminal of the field effect transistor,
• adjusting the amplitude of the intermediate signal such that the same causes the potential swing between the gate terminal and the source terminal to at least partly be in the quadratic region of the transfer characteristics of the field effect transistor.