Amplifier e.g. audio amplifier, has three-pole e.g. MOSFET, comprising high impedance control input whose potential determines potential of current output of three-pole, where current output is connected with screen grid

摘要

The amplifier has a multi-grid tube i.e. pentode (Xt1), comprising a control grid and a screen grid, and interconnected with a three-pole (N1) e.g. MOSFET. The screen grid is connected to a current output of the three-pole. An anode of the multi-grid tube is connected to a current input of the three-pole. The three-pole comprises a high impedance control input whose potential determines potential of the current output connected with the screen grid, where amount of output current (Ig2-1) at the current output of the three-pole is equal to amount of input current (Ig2-2) at the current input.