Capacitor proximity sensors
a) are actuated by both conductive and nonconductive materials.
b) are actuated by conductive materials only.
c) produce an electromagnetic field.
d) have a long sensing range.
The correct answer and explanation is :
The correct answer is c) produce an electromagnetic field.
Explanation:
Capacitor proximity sensors are a type of non-contact sensor that detects the presence of an object without physically touching it. These sensors work by detecting changes in capacitance caused by the presence of a target object. Here’s a breakdown of how these sensors function:
- Capacitive Sensing Principle: Capacitor proximity sensors utilize the principle of capacitance, which is the ability of two conductive objects to store an electrical charge. The sensor generates an electromagnetic field, which is typically a weak electric field, around its sensing area. When an object enters this field, it alters the local capacitance, either increasing or decreasing it, depending on the nature of the object.
- Electromagnetic Field: The electromagnetic field is essential for detecting objects in the sensor’s range. Unlike inductive sensors, which rely on the magnetic properties of conductive materials, capacitive sensors are sensitive to changes in the electromagnetic field caused by any material that affects capacitance.
- Object Detection: Capacitor proximity sensors can detect both conductive and non-conductive materials. For example, a sensor may detect a person (a conductive object) or a plastic object (a non-conductive material), provided that the material influences the capacitance of the field in some way. This is different from inductive sensors, which only detect metals (specifically ferrous metals).
- Sensing Range: Capacitive proximity sensors tend to have a relatively shorter sensing range compared to inductive sensors, especially when compared to other types of proximity sensors like ultrasonic or photoelectric sensors. The range is typically limited to a few centimeters but can vary depending on the size of the sensor and the sensitivity settings.
In conclusion, capacitive proximity sensors produce an electromagnetic field, and their ability to detect both conductive and non-conductive materials makes them versatile for various applications. However, they generally have a shorter sensing range compared to some other sensor types.