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How is three pin switch called?

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Alloy

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Hey
English is not my primary language, but I need a switch that has 3 connections (let's say pin 1, 2, and 3) and has two states: 1 connect to 2 (pin 3 disconnected), and 1 connected to 3 (pin 2 disconnected).

How is such element named and how to look for that on Aliexpress?
How is such element called in Eagle?

This element will be used as a switch for MCU circuit, so it's for lower power.

Thanks in advance!
 

It's called double-throw (DT) switch.
 
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More precisely it's referred to as a SPDT Single pole (1) double throw (2|3) see .
 
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Thanks. That's what I wanted.
I've checked that sparkfun article.
And the 4-pin version is called 4PDT, right?

I just wonder why there are mostly such the middle-sized switches and no little switches and no big switches...
 

Audioguru said:
Usually pin 2 connects to pin 1 or pin 2 connects to pin 3.
Click to expand...

I just used the OPs nomenclature for clarity not for physical pinout information of the switch.

- - - Updated - - -

Alloy said:
And the 4-pin version is called 4PDT, right?
Click to expand...
yes

I just wonder why there are mostly such the middle-sized switches and no little switches and no big switches...
Click to expand...
Do you mean the physical size of the switch or the number of poles?

Physically big switches are usually things like knife switches and little switches are usually called micro switches or similar.
 

A mechanical 3 pin switch uses center pin (POLE) to switch to Normally Open (NO) or closed (NC) positions.
It depends if it is a slide switch, , rotary or toggle switch.

For low current, you may need to bypass cap to clean non gold plated contacts from oxide.
For better reliability, gold plated switches are used ( <2A)

For simply switching on CPU power , a 2 pin slide switch is all that is normally used on PCB or a toggle switch on Panel or a push-push button for toggle ON-OFF but still single pole single throw or SPST or 1P1T

For semiconductor double throw switches we use two switches P(+) & N(-) to make a bipolar switch like CMOS.

For single POLE , we can use a semiconductor " High Side Switch" common to automotive use.
A double pole (2T) electronic switch for power is usually called a 2 pole bridge driver.
 
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