SJG-2083CS Online Toroidal Conductivity Meter BOQU Toroidal conductivity sensors consist of two toroidal coils inside an inert plastic case (these toroidal coils are how the “toroidal” sensor gets its name). One toroid emits an electric field, and the other detects a small induced electric current proportional to the number of ions present (this induced current is why toroidal sensors may also be called “inductive” sensors). The two toroids form a transformer whose coils are interconnected by the resistance of the surrounding electrolytic solution. In contrast to traditional contacting conductivity sensors, BOQU toroidal conductivity sensors do not cause polarization, do not become fouled, and rarely require maintenance. Reduced maintenance needs and increased reliability make toroidal conductivity sensors more cost-effective than contacting sensors over time.