A proximity sensor can be either AC, DC, or AC/DC type, depending on how it is designed and where it is used. The power supply type mainly depends on the sensor model and the application it is meant for.
In most modern automation systems, DC proximity sensors are the most common. These sensors usually operate at 10 to 30V DC and are available in both NPN and PNP output types. DC sensors are widely used because they are easy to connect with PLCs, controllers, and other low-voltage control circuits. They also switch faster, making them ideal for applications that require quick response times, such as counting parts on a conveyor, detecting metal in machining systems, or positioning robotic arms.
On the other hand, AC proximity sensors are designed to work with 100 to 240V AC power. They are often used in older or heavy-duty industrial systems that use AC control circuits. These sensors directly switch AC loads such as contactors, relays, or indicator lamps. However, AC sensors are less common today because most modern automation systems have shifted toward DC-powered devices for safety and compatibility reasons.
There are also universal proximity sensors that can handle both AC and DC supply voltages. These are labeled as AC/DC sensors and are very useful when the power supply type is not fixed or when the same sensor design needs to be used across multiple systems.
For example, Omron proximity sensors come in AC, DC, and AC/DC models, allowing users to choose according to their control circuit. DC sensors are generally preferred in advanced automation panels, while AC types are still used in older machines or where direct switching of AC loads is required.
So, a proximity sensor can be AC, DC, or AC/DC, depending on its design. DC types are most common in modern automation systems for their speed, safety, and compatibility, while AC versions are used mainly in traditional or heavy-load applications.