Modulated power supply is necessary for final stages of AM transmitters, transmitters with Gunn diodes in GHz frequencies. This amplitude modulating supply provides (in idle mode) an output voltage which can be adjusted with P1 between 6 and 8V; and when is modulated the output voltage is between 3 and 10V. Frequency domain is from 200Hz to 30kHz.
Without external load, the current consumption is 5mA. If T2 is cooled enough the modulation power supply cand deliver up to 800mA at 6V.

AM power supply circuit schematic

AM power supply