Proximity Sensor Question

Hi everyone,

I have a simple question regarding proximity sensors. How many types are there exactly? From my understanding there are inductive proximity sensors, capacitive proximity sensors and photoelectric proximity sensors. Furthermore, does an ultrasonic sensor categorize as a proximity sensor as well?

Thanks,
24V

Well...

prox·im·i·ty
/präkˈsimədē/
noun
nearness in space, time, or relationship.

Based on the definition almost any sensor could be called or used as a proximity sensor.

Thanks for clearing that up for me I appreciate it!

However, in everyday use, only the inductive sensors are called "proximity sensors" or just "proxes". This is not the absolutely correct use of the words but this is the way it is.