A motor-pump unit including an electric motor and a pump. The voltage regulator includes an operational amplifier and a voltage trim circuit. This method includes depositing a filler material in the trench and etching the filler material to a particular depth that is less than the particular thickness of the insulator stack material. This configuration permits easy calibration of the magnetoinductive flowmeter while during operation, any deviation from a calibrated condition can be detected reliably. The locking mechanism is coupled to the steering column and comprises a first member including a first diameter; and a second member including a second diameter.