DEVICE FOR SENSING MECHANICAL CONTACT OR LOAD/NO-LOAD CONDITIONS

摘要

A device for sensing mechanical contact includes an oscillatory circuit (S) with a generator (G) which is adapted to keep the circuit oscillating, and a mechanical vibrator (V) which is coupled to oscillate together with the oscillatory circuit. The vibrator has a vibratory component (50) with a sensor part (52) which is adapted to be contacted or loaded and thereby changes the oscillation of the vibrator. Moreover, the sensing device includes equipment (O) for establishing changes in the phase between current and voltage and/or changes in the signal level in the oscillatory circuit. When the sensor part (52) is touched or loaded there will be a change in the oscillation, and through the coupling to the oscillatory circuit this causes a change of the quality factor Q and/or the resonant frequency of the circuit. Such changes cause in turn a change in the phase between current and voltage and a change in the signal level. Either of these changes can be established or measured and is used to control or initiate switching functions.