A basic magnetic level sensor is a type of device used to detect the level of a liquid inside a container or tank. It operates based on the principles of magnetism and uses a float with a built-in magnet to determine the liquid level. Here's how it works:
Float and Magnet Assembly: The sensor consists of a float that is buoyant in the liquid being measured. The float is typically made of a material that is resistant to the liquid and its properties (such as chemical composition and temperature). The float contains a small, powerful magnet securely embedded within it.
Sensor Housing: The sensor housing is mounted on the exterior of the tank or container. It is positioned at a point where the liquid level needs to be monitored. The housing is typically made of non-reactive materials and contains a reed switch or Hall effect sensor.
Reed Switch or Hall Effect Sensor: The sensor housing contains either a reed switch or a Hall effect sensor. These are both types of magnetic sensors capable of detecting the presence of a magnetic field.
Reed Switch: A reed switch is a simple switch that consists of two thin metal reeds encased in a sealed glass tube containing inert gas. When a magnetic field is applied near the reed switch, the reeds become magnetized and attract each other, effectively closing the circuit. This change in the circuit's status is used as a signal to indicate the presence of the float's magnet.
Hall Effect Sensor: A Hall effect sensor uses the Hall effect, which is a phenomenon where a voltage difference is generated across an electrical conductor when it is subjected to a magnetic field perpendicular to the current flow. Hall effect sensors can directly measure the strength of the magnetic field, providing a more precise and continuous level measurement.
Magnet Movement: As the liquid level changes within the tank, the float with the embedded magnet moves up or down accordingly. When the liquid level rises, the float and its magnet also rise. Conversely, when the liquid level falls, the float and magnet descend.
Signal Output: As the float's magnet moves closer to the sensor housing, it triggers the reed switch to close (in the case of a reed switch) or generates a varying voltage (in the case of a Hall effect sensor). This change in the sensor's output is then processed by an electronic circuit connected to the sensor.
Level Indication: The electronic circuit processes the signal and translates it into a readable format, which could be a visual display, a digital signal, or an analog output. This indication provides information about the liquid's level inside the tank.
In summary, a basic magnetic level sensor utilizes a magnet-equipped float to determine the liquid level within a container or tank. The movement of the float's magnet is detected by a reed switch or Hall effect sensor, which then generates a signal used to indicate the liquid level.