High frequency amplifier circuit with overvoltage protection arrangement, has transistor protection circuit after overvoltage protection tapping with normally off transistors

摘要

The circuit has two amplifier branches (9a,9b). The overvoltage protection arrangement is connected in the transmission direction between an input transformer (13) and an output transformer (15). There is an overvoltage tapping (19) connected upstream of the amplifier to be protected. The transistor protection circuit (31a,31b) is connected downstream of the overvoltage protection tapping in the overvoltage noise signal direction. This has transistors that are normally blocked and that are switched on if a residual overvoltage occurs to limit the maximum permissible voltage.