Terahertz Linear and Nonlinear Dynamics in Confined Magnetoexcitons

In amplifier circuit arrangements for low-distortion transmission of audio signals a transformer is provided in order to isolate a source circuit from an amplifier of the amplifier circuit arrangement. Good transmission characteristics, however, can only be obtained in such circuit arrangements by using transformers of comparatively great dimensions. In order to achieve improved transmission characteristics and yet design the transformer in such a manner as to have small size, to be of low weight and inexpensive, the amplifier of the amplifier circuit arrangement is provided with a negative feedback circuit. This negative feedback circuit is connected to the source circuit by using a transformer connected in series with the current-voltage source of such source circuit.