When you have a question about process automation that needs a short answer, let us know with #WishIknew and #Visaya! We’ll reply with a #WishIknew post. It’ll give a quick explanation, then some related articles, videos, or reviews if you want to know more.

I wish I knew how a level switch works!

You can find all kinds of level switches out there, from mechanical to electronic versions. Each type works differently and needs certain conditions in your process. You should scale out to find out the best model and principle for your application. Otherwise, you could run into big problems.

Here we’ll talk about three common types – vibration, capacitance, and float level switches. Different brands may have advanced features or patented technology, but in the end, they’ll work similarly.


  • Vibrating switch or vibration fork: This sensor works based on the principle of the tuning fork. We have an article with more details about this idea here. You have two prongs vibrating at their natural frequency. When product covers the prongs, the frequency drops. The device then sends an alert of this change.
  • Capacitance level switch: This switch uses the same principle as continuous level measurement devices. The probe and tank walls act as the capacitor plates, and the product as the dielectric. If the level reaches the sensor, then the capacitance changes and the sensor sends its signal.
  • Float level switch: This device is a mechanical solution for liquids and uses buoyancy to work. You can find one of these in your toilet tank! When your product reaches the float, the sensor alerts the system to stop the flow.


Recommended articles