This circuit is designed to detect the presence or absence of aqueous fluids. An ac signal generated on-chip is passed through two probes within the fluid. A detector determines the presence of the fluid by using the probes in a voltage divider circuit and measuring the signal level across the probes. An ac signal is used to prevent plating orills solving of the probes as occurs when a de signal is used.
A pin is available for connecting an external resistance in cases where the fluid impedance is not compatible with the internal 13Kohm divider resistance.