Adjusting device for a valve flap, exhaust gas turbocharger, operating method

The device (2) has an electrical servomotor (1) comprising a rotor (5) and a commutator (9), where the rotor is operatively connected with an adjusting rotor shaft (3) operating a valve flap to urge the valve flap to a close position by rotating the adjusting shaft in a close rotation direction. The commutator is formed according to commutation in the close rotation direction with low speeds of the servomotor. The commutator comprises a mechanical commutator (6), which rotates according to commutation in the close rotation direction in which the rotor is aligned. Independent claims are also included for the following: (1) a supercharger comprising a waste gate valve (2) a method for operating a positioning device.