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.. _cpn_limit_sw:

Micro Switch
========================

|img_micro_switch|

The construction of a micro switch is really simple. The main parts of the switch are:

|img_micro_switch2|

* 1.Plunger (Actuator)
* 2.Cover
* 3.Moving piece
* 4.Support
* 5.Case
* 6.NO terminal: normally open
* 7.NC terminal: normally closed
* 8.Contact
* 9.Moving arm


After a micro switch makes physical contact with an object, its contacts change position. The basic working principle is as follows.

When the plunger is in the released or rest position.

* The normally closed circuit can carry current.
* The normally open circuit is electrically insulated.

When the plunger is depressed or switched.

* The normally closed circuit is open.
* The normally open circuit is closed.

|img_micro_switch1|

 **Example**

* :ref:`py_micro` (For MicroPython User)
* :ref:`ar_micro` (For Arduino User)
* :ref:`per_service_bell` (For Piper Make User)