why is a 3way sw called a 3way not a 2way

[mivey]

A three way switch is a system that controls a load with two switches.
It just so happpens that two components of the switching system are SPDT switches.

A two way switch is also a system that controls a load with two SPDT switches.

Operationally they perform the exact same function, but the are wired differently.

The two-way has two current paths, the three-way has three.

I re-edited # 65.
It's no big deal, but thats the way is.

GO AHEAD MESS WITH A+

I thought a two way switch was a SPST switch

 

[480sparky]

I thought a single pole double throw switch had four points on it. A threeway only has three points. Wish I had a good graphics program, I'd draw a little picture.

A SPDT is another term for what we call a 3-way.

If it's got 4 terminals, and has "On/Off" on it, then it's a DPST.

 

[mivey]

I thought a single pole double throw switch had four points on it. A threeway only has three points. Wish I had a good graphics program, I'd draw a little picture.

A SPDT has 3 points. A DPST has 4 points. I think a four way is like a DPDT switch?

[edit: I see 480sparky has the 1st part of my answer already. Do you have a picture of the 4-way?]

 

[480sparky]

A SPDT has 3 points. A DPST has 4 points. I think a four way is like a DPDT switch?

[edit: I see 480sparky has the 1st part of my answer already. Do you have a picture of the 4-way?]

Like dis?

 

[quogueelectric]

Does anyone know what that means?

[edit: post 69 is useless.]

[edit: please note your edits. your posts aren't making any sense.]

Do mess with A+ is a shot a Rattus's signature of Dont mess with B+
which means Chassis supply voltage in a piece of electronics I believe but it could mean just about anything around here. :grin:

 

[dwcaveney]

Good Night!

Good Night!

Delete*****

 

[iwire]

A three way switch is a system that controls a load with two switches.

A switch is a system?

 

[Smart $]

Yeah, like Edison invented the light bulb and Marconi made the first radio.

Edit: And you can't have a step up or step down transformer using DC.

(Swan invented the light bulb, Tesla made the first radio and take a look at the coil in your car....)

An ignition coil does not operate on DC, even though it has a DC power source. It does operate on "timing" pulses, thus the requirement of a changing magnetic field is satisified.

 

[mivey]

Like dis?

That's one. Do you have a DPDT version (two points on one side, then 4 points (this is the DPDT), some crossed wires on the DPDT output, then on to 2 points, with the whole package making a 4-way?

 

[480sparky]

...the three-way has three.

Common to Traveller 1, Common to Traveller 2, and _________?

Seriously. I'm not trying to be argumentative. But to me, a 3-way is a SPDT. By your description here, you're calling it a two-way.

 

[dwcaveney]

Yes it is!

Yes it is!

DELETE .....

 

[iwire]

Have you ever made a three way with one switch?

No, I have never made a 3 way switch, I have installed a few.

But you said 'a switch' is a system, a single switch is not a system.

A three way switch is a system that controls a load with two switches.

Maybe you meant that '3 way switch' is the name of a switching system?

 

[peter d]

How can something as simple as a 3-way (or 2-way) setup turn into an endless discussion like this?

 

[stickboy1375]

How can something as simple as a 3-way (or 2-way) setup turn into an endless discussion like this?

Because we have nothing else to discuss?

 

[dwcaveney]

DELETE

 

[iwire]

A single SPDT operates SPST unless connected to another SPDT so, yes it takes two SPDT switches to "make" a three way in a building project.

Of course it takes two, that was not what I asked.

Do you still feel

A three way switch is a system

See I know you are here to help us all so I want to get it right. :smile:

 

[mivey]

That's one. Do you have a DPDT version (two points on one side, then 4 points (this is the DPDT), some crossed wires on the DPDT output, then on to 2 points, with the whole package making a 4-way?

Kind of like this:

 

[480sparky]

A single SPDT operates SPST unless connected to another SPDT so, yes it takes two SPDT switches to "make" a three way in a building project.

But a SPDT does not require another SPDT in order to operate. It can also connect one source of power to two (non-coincidental) loads.

 

[dwcaveney]

Switch

Switch

Yes I do. It takes 2 SPDT switches to make one "Three Way Switch"

And by the way a single pole double throw switch is not a three way switch,

It is a SINGLE POLE DOUBLE THROW SWITCH

Call it what you like, but thats what it is.

[edit] Thank you Bob for your interest in this thread

 

[480sparky]

Yes I do. It takes 2 SPDT switches to make one "Three Way Switch"

And by the way a single pole double throw switch is not a three way switch,

It is a SINGLE POLE DOUBLE THROW SWITCH

Call it what you like, but thats what it is.

So when you go to the supply house and ask for "A 3-way switch", this is what they give you?