What kinds of proximity switches are there?

2019-07-01 1725

Passive proximity switch

The switch does not need a power supply and passes through the closed state of the magnetic induction control switch. When the magnetic or ferrous flip-flop is close to the switching magnetic field, it is controlled and closed by the internal magnetic force of the switch. Features: No power supply, non-touch, maintenance-free, environmental protection.

Eddy current proximity switch

This kind of switch is sometimes called inductance proximity switch. It uses a conductive object to generate eddy current inside the object when it is close to the switch that can generate electromagnetic field. This eddy current reacts to the proximity switch, causing the circuit parameters inside the switch to change, thereby identifying whether there is a conductive object approaching, and then operating the switch on or off. It is necessary that the object detected by the proximity switch be a conductor.

1. Principle: Vibrator is composed of inductance coil, capacitor and transistor, and generates an alternating magnetic field. When a metal object is close to this magnetic field, eddy current will occur in the metal object, and then the vibration will stop. This change is amplified by the rear pole and converted into the output of transistor switch signal.

2. Features: A, good anti-interference performance, high switching frequency, more than 200 HZ. B, can only sense metal