The operating principle of a float switch based on a reed contact relies on the use of a reed switch as the switching element. A float switch consists of a buoyant body, also known as a float, which floats on the liquid surface. The buoyant body is equipped with a magnet. When the liquid level changes, the buoyant body moves accordingly, either upward or downward. When a certain level is reached, the magnet approaches the reed contact. The reed contact consists of two ferromagnetic contact blades placed within a glass capsule. These blades are separated by a small air gap. When the magnet of the buoyant body reaches the reed contact, the magnetic field attracts the ferromagnetic blades, bringing them together. This closes the contact blades, completing the electrical circuit. This closed circuit can be used to send a signal, for example, to trigger an alarm or control a motor.

The electronic temperature switch/controller monitors the temperature of the liquid in the container. A temperature sensor is used to measure the current temperature of the liquid and convert it into an electrical signal. The signal is forwarded to a microcontroller or electronic control unit. The microcontroller processes the temperature signal and compares it to a predefined setpoint. Depending on whether the measured temperature meets, falls below, or exceeds the setpoint, the microcontroller controls the corresponding output components. These can be heating elements or cooling devices, which are activated or deactivated to regulate the temperature in the container.