A measuring circuit for the output of a power amplifier and a power amplifier comprising the measuring circuit comprises a first transistor (4f). The output current (27) of the first transistor (4f) is characteristic of the output current (28) of the amplifier (20), in particular, the above is essentially proportional to the output current (28) of the amplifier (20). The first transistor (4f) is controlled in parallel to at least one second transistor (4a-4e), driving the amplifier output (8).