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Post Info TOPIC: Two way DC switching ie. One lamp two switches
Phil C


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Two way DC switching ie. One lamp two switches
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hi all. 

A few days ago a mate asked me about two way swiching on DC, I scratched my head and said why not, so off to L and H we trundled and bought two mech plates a length of strap wire and started to experiment. 

I set up a normal two switch mechs with a strap between NO and NC poles (NO to NO and NC to NC) the positive on the common of switch one and the switched positive from the other common, with negative on the other side of the lamp. 

By heck it worked, no need for SPDT as some may suggest, it's exactly the same as 240 volt wiring, replacing active with positive and switched active with switched positive. 

Whatever you do don't forget the fuse. 

Phil. 



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DeBe


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For those that like a circuit using 2 switches.2 WAY SWITCH.jpg



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Phil C


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image.jpgOr.



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PeterD


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Phil C wrote:

By heck it worked, no need for SPDT as some may suggest,

 Phil, sorry to inform you but you have just used two SPDT switches.



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Joe50


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Thanks Phil and DeBe, I've been meaning to sit down and figure out such a circuit for the two LED lights I want to put into the ceiling so I can turn them on or off no matter which end of the bus I am.

Cheers
Joe


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Phil C


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PeterD wrote:
Phil C wrote:

By heck it worked, no need for SPDT as some may suggest,

 Phil, sorry to inform you but you have just used two SPDT switches.

 You are absolutely correct PeterD. It seems my theory and now practical has left me after all these years, my apology if any were misled. 



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KFT


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Phil C wrote:
PeterD wrote:
Phil C wrote:

By heck it worked, no need for SPDT as some may suggest,

 Phil, sorry to inform you but you have just used two SPDT switches.

 You are absolutely correct PeterD. It seems my theory and now practical has left me after all these years, my apology if any were misled. 

 Have you been out in the vineyard or inside in the winery?



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Avagreatday.

Kathy and Frank currently at Home near Quirindi NSW
Phil C


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KFT wrote:
Phil C wrote:
PeterD wrote:
Phil C wrote:

By heck it worked, no need for SPDT as some may suggest,

 Phil, sorry to inform you but you have just used two SPDT switches.

 You are absolutely correct PeterD. It seems my theory and now practical has left me after all these years, my apology if any were misled. 

 Have you been out in the vineyard or inside in the winery?

 Bit of each Frank, nice of PeterD to point out my boo boo



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Big Gorilla


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To convert a single switch to two way, use this diagram with 2 x 2 way switches. This is ok for 240 volts in a fixed installation in a house but MUST NOT be used for 240 volts in a caravan or MH, as double pole switching is required. Two way switching for a 12 volt installation is ok...

 I don't understand SPDT. What is it ?

Two Way.jpg



-- Edited by Big Gorilla on Monday 23rd of March 2015 09:58:05 AM

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Peter_n_Margaret


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Slightly different, but I have some lights on the back of the OKA that are both reversing lights (powered from the vehicle system) or separately switched inside the vehicle and powered by the house batteries.

I used some blocking diodes to make sure I did not get a connection between the house and crank supplies.

Cheers,
Peter

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DeBe


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SPDT Is Single Pole Double Throw which is what is in the discution. 



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Phil C


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You know, when I taught this many years ago there was a lot of discussion on this very issue. The switch I used LOOKS like a DPST with two active poles and one throw. Just thought I'd put it out there.

we all know that double pole means literally two switches. However it can be confusing, mind you I'm not covering my butt for my boo boo, just plain forgot. no



-- Edited by Phil C on Monday 23rd of March 2015 01:24:38 PM

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oldtrack123


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Phil C wrote:

You know, when I taught this many years ago there was a lot of discussion on this very issue. The switch I used LOOKS like a DPST with two active poles and one throw. Just thought I'd put it out there.

we all know that double pole means literally two switches. However it can be confusing, mind you I'm not covering my butt for my boo boo, just plain forgot. no



-- Edited by Phil C on Monday 23rd of March 2015 01:24:38 PM

  Hi 

 Single pole double throw only require 3terminals

 Double pole single throw only require 4 terminals

Double pole double throw require 6terminals

But beware all 4 terminal swithes may not be double pole single throw.

PeterQ



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Phil C


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If I remeber correctly the pole was the common terminal and the throw the positions the switch could be in.

Now that going back a long time.

Hope you are well PeterQ.

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