Sanitary appliance comprising a sensor circuit and use thereof

A method of using a sensor circuit to sense electrical conductivity of an aqueous solution in a sanitary appliance or a variation in the electrical conductivity, the method comprising:

• sensing by the sensor circuit an electrical conductivity of an aqueous solution in a sanitary appliance based on a signal generated by a signal generator or a variation in the electrical conductivity of the aqueous solution, wherein:
• the sensor circuit includes:
• a primary circuit including the signal generator,
• a secondary circuit that is inductively coupled to the primary circuit and that includes a capacitive sensor having a first and second electrode, and
• an output circuit for conditioning a response transmitted from the secondary circuit into an output signal indicative of sensed electrical conductivity or indicative of the variation in the electrical conductivity,
• the aqueous solution constitutes a medium of the capacitive sensor,
• the primary circuit comprises a resonant tank circuit comprising at least one capacitor and an inductor coupled in parallel to ground, and
• the secondary circuit is coupled to the primary circuit via the inductor of the resonant tank circuit.

A method of using a sensor circuit in a sanitary appliance, the sanitary appliance comprising a tube or chamber that has a tube wall and that is configured for keeping an aqueous solution with a water surface, the method comprising:

• sensing by the sensor circuit a variation of a location of the water surface adjacent the tube wall, relative to a reference location, wherein:
• the sensor circuit includes:
• a primary circuit including a signal generator configured for generating sensing signals,
• a secondary circuit that is inductively coupled to the primary circuit and that includes a capacitive sensor having a first and a second electrode, and
• an output circuit for conditioning a response transmitted from the secondary circuit into an output signal indicative of the variation of the location of the water surface adjacent the tube wall, relative to the reference location,
• the aqueous solution constitutes a medium of the capacitive sensor,
• the primary circuit comprises a resonant tank circuit comprising at least one capacitor and an inductor coupled in parallel to ground, and
• the secondary circuit is coupled to the primary circuit via the inductor of the resonant tank circuit.