Kā lietot a multimetrs to izmērīt tuvums slēdži
A tuvums slēdzis, as the name suggest, is a switch that only works when it is "close". The proximity switch should be classified as a position switch, and the biggest difference from our common travel switches is that the proximity switch can complete the position measurement work without touching the measuring object.
In short, the essence of proximity switches is still switches, but to working principles are different. Currently, common proximity switches on the market are aptuveni sadalīts into the following categories:
Fotoelektrisks tuvums slēdzis: Caur atstarojums gaisma, kad ir ir šķērslis bloķēšana izstarotā gaisma, the ierīce būs ģenerēs an on or off signāls.
Hall type proximity switch: People may not be familiar with the term Hall, but in fact, Hall is a form of circuit that is sensitive to magnetic substances. When a magnetic object is detected, the circuit will change, and through the conversion circuit, the corresponding on or off signal will be output:
Capacitive proximity switch: When it comes to capacitive proximity switches, it is important to understand the issue of dielectric constant. When an object pass between the two electrode plates of a capacitor, the dielectric constant changes, who ģenerē a signal that is then converted and output through a circuit.
Although it is also a switch, the measurement of this proximity switch is somewhat special. If we measure it directly, we will definitely not be able to measure anything, because this proximity switch requires power supply during normal operation, just like an electrical appliance, which needs to be connected to a power supply, and most of them are DC 24V.
After supply power to the proximity switch, we also need to understand its internal wiring method. Let's take the three-wire proximity switch as an example. Friends who know some circuit knowledge can easy see that the on-off of the proximity switch is related to a tranzistors. Kad an objekts is sensed in the main circuit of the proximity switch, the on-off change inside the circuit will occur, kas būs forma a slēgta ķēde at abi gali of the load in the figure below, That is, a 24V power supply is added both sides of the load, kas ir faktiski darba princips of the tuvums slēdzis.
