Capacitance Level Sensor

Sensors come in many forms to measure a variety of mechanical parameters (such as strain and position), environmental parameters(temperature, pressure and humidity) and samples (such as materials, tissue and organisms). Changes in the sensed environment lead to a corresponding variation in the sensor's impedance. This impedance variation, which comprises inductance, capacitance and resistance or the complex impedance itself, is measured to a high precision and accuracy on a short timescale appropriate for the sensor. As impedance often changes with frequency, a sensor's impedance spectrum provides an additional fingerprint for the measured sample or environment. The vast array of sensors currently available includes chemical sensors and biosensors. Chemical sensors are typically capacitive: the presence of an analyte in the dielectric causes a change in the capacitance. Impedimetric biosensors are used to measure tissue or organisms in a liquid medium (static or flowing), and in most cases are non-destructive and label-free.