Vibrating Fork Level Switch is electronically stimulated fork vibrates at itâ€™s mechanically Resonance frequency of 125 Hz when the fork is free of the service Material. The resonance is caused by the piezoelectric crystals. One of the Piezo crystals produces a small voltage which is transmitted to the Switching amplifier. If the fork is covered by the bulk material, a Damping effect is produced and the piezo crystal does not produce the Voltage and the amplifier will switch and a corresponding signal output is Actuated. The vibration of the fork has self-cleaning properties.