Level sensors work by producing an electrical output corresponding to specific values representing the media level being monitored. The electrical output is an indirect representation of the media level, which means it is possible to calibrate and convert the signal output into an actual reading of the medium being monitored.

An example of a level switch at work is a fuel tank sensor. The level switch installed in the fuel tank produces an electrical output that corresponds to the fuel level remaining in the tank. The level sensor electrical output provides input or data to a fuel gauge that displays the reading to the driver.

Level switches detect the medium level inside the tanks where they are installed. They use on and off signals to indicate when the medium reaches the empty, filled, or any other specific level defined by a project. Because level switches are usually fixed at specific points in a tank, they are not prone to external influence, including ripples and vibrations. Therefore, level switches are highly reliable and can be used more repeatedly than other types of level detectors.

Level switches or level sensors are designed to monitor, maintain, and measure different media types, including solids and liquids such as water, gasoline, and viscous fluids. Once the device detects the media, it converts the perceived element into electric signals. APG Sensors is one of the leading suppliers of level switches or sensors in the U.S. Our products are used in many industries, including manufacturing and automotive. You can also find our level switches in many household appliances such as refrigerators and icemakers. A considerable benefit of level switches is they provide an affordable automation solution.

APG level switches can be used to monitor different types of media. We have different types of level sensors with wide-ranging applications. The type of media you want to monitor determines the one you choose. Our level sensors fall into two main categories:

- Point level sensors
- Continuous level sensors

As the names suggest, point-level sensors monitor media at specific points while continuous level sensors monitor media as they rise and fall. Examples of point level sensors include:

- Capacitance
- Conductivity
- Vibrating
- Optical
- Ultrasonic
- Float switches
- Radar



The name of this sensor is derived from its two fork-shaped tines. The medium being measured causes the sensor to vibrate. The vibration frequency corresponds to the medium level in the vessel. Some of the benefits of vibrating level sensors include:

- Affordable
- Compact
- Easy to install and maintain

On the downside, vibrating sensors:

- Must be in touch with the medium being monitored

This level switch has wide-ranging applications in the food and beverage, mining, and chemical processing industries.


Optical level sensors convert light rays into electrical signals corresponding to the level of specific media being monitored. The strengths of this type of switch level include:

- No moving parts hence highly reliable
- Not prone to interference by pressure or temperature
- Small size
- Suitable for liquid applications

On the other side, the drawbacks of optical level sensors include:

- They require frequent cleaning to rid the lens of dirt and other impurities

Optical level sensors are suitable for oil, coolant, and hydraulic applications. They are mainly used to prevent run-dry conditions.


As the name suggests, this device measures medium levels by analyzing their electrical conductivity. It features a pair of electrodes that apply alternating current to the medium being monitored. Contact between the medium being monitored and the level switch generates an electrical signal corresponding to the medium's level in the vessel. Some of the strengths of conductivity sensors include:

- They have no moving parts hence highly reliable
- They are affordable
- Simple to use

The drawbacks include:

- They must be in contact with the medium being measured
- They often erode with 12:39:07
- They can only be used with electrically-conductive media


This sensor works with a float that raises and lowers with the medium levels in the container. The rising and falling of the medium levels may cause the device’s circuit to open or close. Some of the benefits of float switches include:

- They provide a direct measurement of medium levels
- They are affordable
- It can work without an electrical outlet

On the downside, float sensors:

- Must touch the medium being monitored
- They are not as reliable due to their moving parts
- It can be quite large
- Only measure how high or low a medium is and not any other variable

Float switches are mainly used in liquid storage tanks to provide media high and low indications.


This type of sensor works by producing electrical signals that detect the medium level in a vessel or container. Some of the benefits of capacitance level sensors include:

- Small size
- More affordable than other types of sensors
- Provide accurate readings

On the downside, capacitance level sensors:

- Require calibration
- It can only be used with specific liquids

A common application of capacitance level sensors is in the storage tanks of water treatment facilities.


This device measures media levels using ultrasonic waves. It emits ultrasonic waves and measures the amount of time it takes for the waves to reach the source and bounce back. Ultrasonic sensors are:

- Reliable because they lack moving parts
- Compact
- Do not require contact with the medium being monitored
- Unaffected by media properties
- Self-cleaning due to the vibrations they produce

The drawbacks of ultrasonic switches include:

- They are a bit pricey
- They can be affected by the environment in some situations

Ultrasonic sensors are mainly used in the chemical processing and manufacturing industries.


This type of level switch works by transmitting microwaves. They feature antennas that detect the microwaves produced by the device. They measure media level by analyzing the amount of time it takes for the microwaves to reach the media and bounce back to the device. Radar level sensors are:

- Not affected by the elements including pressure, dust, and temperature
- Can measure media in different forms, including powders, solids, liquids, and pastes
- Extremely accurate
- Do not require calibration
- Do not have to touch the media being monitored

The drawbacks of radar sensors include:

- They can be quite pricey
- Their detection range is limited

Level switches have applications in many industries, including cloud systems, petroleum, chemical, power generating, and pharmaceutical industries.

Learn more about the level switches you need for your applications. Please contact APG Sensors today for additional information about our level switches.


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