Abstract: In liquid measuring apparatus, a cable supporting a sensing plate is attached to a drum that is connected via a magnetic clutch with the drive shaft of a servomotor. The servomotor is supported in a pivot mount which is flexibly rotatively connected to the apparatus housing. In response to liquid level changes, a contactless sensor generates a signal which is compared with a balance of moments reference signal in a comparator to develop a deflection signal which, after conversion into frequency pulses in fast servocontrol circuitry, activate the servomotor in one direction or the other as determined by a polarity switch activated by a directional decoder. Inaccuracies due to parts vibrations are compensated for. Also, measurement disturbances caused by waves at the surface of the liquid are avoided with the aid of slow servocontrol circuitry which, after a delay, activates the servomotor with an adjustable frequency supplied by an oscillator.