Technology

Capacitance Measurement:
The SeCap™ Difference

Traditionally, capacitance measurements are performed between pairs of electrodes. The problem with the electrode-pair measurement technique is that the system ‘short circuits’ in water-continuous dispersions. The NuFlo Single Electrode Capacitance (SeCap) solution is different. It is based on the measurement of capacitance by a single electrode that utilizes the effect the dielectric constant has on the frequency of an oscillator.

The measurement system is called SeCaP™ because only one electrode is active and not exposed to the measured fluid, meaning short circuiting is never an issue. The basic oscillator circuit operates at a frequency of approximately 20 MHz. The fluid in the vicinity of the capacitor plate affects the oscillating frequency of the circuit. This change in frequency is related to an equivalent change in the dielectric permittivity of the mixture. If a gas is present adjacent to the capacitor plate, no reduction in frequency is observed, but if pure water is present adjacent to the capacitor plate, a much larger reduction in frequency is observed.