A float switch is a simple type of liquid level sensor used to determine whether or not liquid is present. The sensor uses a reed switch and a buoyant piece of plastic embedded with a magnet. If the liquid level drops far enough to let the plastic float reach the end of the slide, the magnet inside the float will cause the reed switch to close, and complete the circuit.

The switch can be used as a low voltage input to a microcontroller digital pin or to directly control loads (relays, solenoids, etc.) up to 500mA. These sensors will only work if placed vertically, if a side mount is required, we also offer a Right Angle version.