# 2-way switch vs SPDT toggle switch



## mymodeltrain (May 14, 2013)

Is there any difference between a 2-way toggle switch from the SPDT toggle switch or they are actually the same?


----------



## Semper Vaporo (Jan 2, 2008)

I'd say they are the same thing. A single input and two possible, but mutually exclusive outputs. Some switches have a 3rd position where neither output is connected (called, center off).


----------



## Pete Thornton (Jan 2, 2008)

mymodeltrain said:


> Is there any difference between a 2-way toggle switch from the SPDT toggle switch or they are actually the same?


If the "2-way toggle switch" has only 3 pins/connections, then they are the same. An SPDT switch specifically indicates it has only 1 pole - it only switches one input between 2 outputs, or vice versa. 
A 2-way toggle has no such indication, so it could have 1 or 2 sets of pins (i.e. it could be a SPDT, DPDT, etc.) It could even switch 3 poles - 3 inputs between 6 outputs.


----------



## Paul Burch (Jan 2, 2008)

Could also be used as a simple on/off.


----------



## mymodeltrain (May 14, 2013)

Thanks all for the information. It takes time for me to learn those concepts.


----------



## toddalin (Jan 4, 2008)

"2-way toggle switch" is ambiguous and is no way to market/buy a switch.


----------



## chuck n (Jan 2, 2008)

MMT

The switch (three position, up, down, and middle) you are asking about might be used to power a siding. One toggle would put power to a rail with a gap. The other two positions would be off.

Or if you have a passing siding throw it in one direction and the passing siding would be active and the main dead, or in the other direction the main would be live and the passing siding dead, or in the center both dead.

In the case of the passing siding you would need two gaps on the same rail on both the passing siding and the main a total of 4 gaps. They would both have to be on the same side of the track.

A switch with on/off would just power a siding or not.

What do you want to do with the switch? That might help us point you in the right direction.

Chuck


----------



## mymodeltrain (May 14, 2013)

chuck n said:


> MMT
> 
> The switch (three position, up, down, and middle) you are asking about might be used to power a siding. One toggle would put power to a rail with a gap. The other two positions would be off.
> 
> ...



Chuck,
I just need a 2-way toggle switch for designing a battery-powered circuit. One way to power the train and the other way is for charging the battery.


----------



## Homo Habilis (Jul 29, 2011)

I use the Battery Conversion Module from G Scale Graphics. It works perfectly and I think it is quite cost effective.


----------



## placitassteam (Jan 2, 2008)

I like to use an SPDT center off switch for battery power and charging. One reason for this that some types of plugs used for charging can actually cause a momentary short as they are plugged in. I burned up some wiring using a phone jack as a charge plug. With the center off switch you can have the switch off while plugging in. Better solution: use a plug that doesn't sort such as a coax or two pin connector.


----------



## Batsco (Mar 30, 2011)

mymodeltrain said:


> Chuck,
> I just need a 2-way toggle switch for designing a battery-powered circuit. One way to power the train and the other way is for charging the battery.


I use a double pole double throw centre off switch for that purpose gives me run /off/charge.
double pole means that I switch bot +ve and -ve lines.


----------



## Pete Thornton (Jan 2, 2008)

> I just need a 2-way toggle switch for designing a battery-powered circuit. One way to power the train and the other way is for charging the battery.


My locos have a socket that includes a 3rd contact that breaks (opens) when you insert the plug. Power to the on/off switch is allowed unless the plug is in - at which point the circuit is interrupted and the battery connected only to the charger. 

There's pics and part numbers in my old PDF: http://gold.mylargescale.com/petethornton/ECLSTS-seminar/Battery%20&%20Radio%20Control2.pdf. 
Not sure if they are still available from RS.
http://gold.mylargescale.com/petethornton/ECLSTS-seminar/Battery & Radio Control2.pdf


----------



## Greg Elmassian (Jan 3, 2008)

Break before make is an important consideration here, helps avoid over current, arcing.

Greg


----------



## placitassteam (Jan 2, 2008)

Pete, That sounds similar to the coax plugs I was using but as Greg says they have to be "break before make" or they short out momentarily as they are inserted.


----------



## Pete Thornton (Jan 2, 2008)

placitassteam said:


> Pete, That sounds similar to the coax plugs I was using but as Greg says they have to be "break before make" or they short out momentarily as they are inserted.


Never had a problem. The RS ones work fine in all my sparkies and steamers.


----------



## Greg Elmassian (Jan 3, 2008)

Yes, shorting momentarily may not produce obvious results, maybe just some pitting, etc.

A difference between what "works ok" and "best practices".

Greg


----------

