Toggle switch confusion..

hey guys,

Im currently trying to collect all the necessery switches for the cockpit, and right now im focused on the light switches..i came across a couple of toggle switches, and i have a question..

whats the main difference between a SPST on-off switch or a SPDT on-none-on in case we do not connect the first pole.. making it a off-none-on .... im a bit confused..shouldt that be the same?... and i still didnt quite get the "NONE" concept..shouldnt that be the same as an off?... thanks in advance!

cheers,

Alex

Hi Alex,
The SPST is a Single Throw while the SPDT is a Double Throw, hence the names. A ON-NONE-OFF switch is an example of a SPST while the ON-NONE-ON is an example of SPDT.

Check this image out:
http://www.carlingtech.com/images/learnmore/throw.jpg

So if you don't connect one leg of a SPDT, you have as you said an ON-NONE-OFF switch and thus an SPST.

NONE just means that the switch isn't relaying (to either in case of the SPDT.

So, the airbus master switch should be working like in the real world with a SPDT 2 way locking lever without the first pole connected ?..correct?

Much appreciated Efe!


Alex

Quote:

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Originally Posted by NNomad007

hey guys,



whats the main difference between a SPST on-off switch or a SPDT on-none-on

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A standard SPDT switch has two positions: the common pole can connect to either one contact or the other.

A SPDT on-none-on switch has three positions: the two standard positions plus a middle position that does not connect to either contact.

"none" simply means a position with no electrical contact.

Hi Mike,

First of all, and im not trying to be corny here...but...... UNBELIEVABLE efford you made to give us rookies true solid bases for developing our sim.. i really apreciate all your help and when i start actually considering building a pit you were one of my main references..again. true honest thanks

Ok.. ."...."none" simply means a position with no electrical contact.... ". ..fare enough and very understandable,.....but still........what does "OFF" means than??...its rather confusing cause they seem to do both the same thing, that is...nothing... so, why some switches with the same specs have the off position and why some have the NONE one?...

maybe its a really stupid question..but..it intrigues me

Cheers and thanks for all the help

Alex

It's confusing because... well, it's confused.

There are standards bodies that publish "official" symbology for switches. Naturally there are American standards and (different) European standards. And it gets worse... There are multiple (different) American standards bodies. There are the electronics dudes, and there are the industrial control dudes each with (different) views on how to describe a switch.

And then there are the switch manufacturers who actually publish the catalogs with pictures and symbols(!) of their products.


So, "off" and "none" pretty much mean the same thing, but don't confuse those with "(off)" or "[off]" or "{off}" which refer to momentarily-off, mechanically-latched-off, and magnetically-latched-off. (IIRC).:wink:

To be honest, I get confused too and end up looking for the drawing legend in a specific manufacturer's catalog just to make sure I understand how that specific switch functions.

Its about time somebody standardizes the standards!

Maybe Barack will solve that...:)

Thanks a lot Mike..if its no bother..i probably throw you some really stupid questions from time to time.. :) im currently at the "im so ignorant plus stupid" phase..so..its coherent..

cheers mate

Alex

yep.... time for change!...:)