The invention relates to an arrangement and to a method for providing a linear transmitter amplifier (11; 50) that remains linear even when the load varies significantly over the passage of time. A detector circuit (14; 48) on the output of the amplifier (11; 50) identifies which of the current or the voltage lies closest to its maximum value. This signal is then used as a real or actual value in a regulating system (17; 40) for linearising the amplifier.