Radio frequency (RF) devices emit high-frequency low-power wireless signals from a probe. When the material touches the probe, the bridge becomes unbalanced and compares the circuit, achieving a change. This will cause a relay output to change state.
Tuning fork sensor
These sensors can use a variety of techniques (typically piezo), probes that vibrate at about 85Hz, and then continuously monitor the vibration changes. The vibration probe that occurs when the tuning fork detects humidity is immersed in the process media. The probe is vibrated by a piezoelectric crystal while the other piezoelectric crystal detects vibration. There are three designs, reeds, probes, and tuning forks. The difference in design is in their configuration and operating frequency. They can be used to detect specific types of liquids. The tuning fork is simple, reliable, and can be cleaned in place. They can tolerate material accumulation and can easily achieve the purpose of self-cleaning coatings.