The switch type is to use the switch value as the output signal, and the corresponding ones are called liquid level switch, pressure switch, temperature switch and flow switch.
Take the liquid level switch as an example. When the liquid level reaches a certain position, the switch acts, open or close. Generally, the liquid level switch has a set of contacts, one normally open and one normally closed.
There are two types of common liquid level switches: float switch and induction switch. The float switch uses the buoyancy effect on the float when the liquid reaches the liquid level to make the float switch act. The inductive liquid level switch calculates the liquid level by the time of transmitting the signal and receiving the signal.
The corresponding pressure switch, temperature switch, flow switch and the liquid level switch have the same principle, and they all switch when a certain value is reached, and are mostly used in electrical control circuits.
Give a simple example to illustrate its specific application, as shown in the figure below:
This is a control circuit for automatic water filling of the container.
When the water level of the water tank is lower than the minimum water level, both YA and YB are closed, and the circuit is automatically connected to the water supply. When the water level of the water tank is higher than YB, YB is disconnected, the circuit is self-maintained, and the circuit is still connected. When the water level is higher than YA, the circuit is disconnected and the water pump stops. With the outward water supply, the water level drops, and when it is lower than the minimum water level, the water supply process is repeated.
