Name for type of toggle sw. that is Mom. Off On?

[Dave Boland]

I have been looking for a small toggle switch for a test box
that is momentary on, off, and on, but can't find one and
don't know if there is a special name for these switches. I
have seen them, but of course can't find them when needed
(yea, what else is knew!). Any help will be appreciated.

Electrically, this switch is like a momentary switch in
parallel with a regular on/off toggle switch. This is one
option, but more work also.

____|____
| |

 

[Mark A. Odell]

I have been looking for a small toggle switch for a test box
that is momentary on, off, and on, but can't find one and
don't know if there is a special name for these switches. I
have seen them, but of course can't find them when needed
(yea, what else is knew!). Any help will be appreciated.

Electrically, this switch is like a momentary switch in
parallel with a regular on/off toggle switch. This is one
option, but more work also.

____|____
| |

Do you mean "normally open momentary" where "off" means the switch is open
an thus passes no current? I would be surprised if www.digikey.com didn't
have them.

 

[John Fields]

I have been looking for a small toggle switch for a test box
that is momentary on, off, and on, but can't find one and
don't know if there is a special name for these switches. I
have seen them, but of course can't find them when needed
(yea, what else is knew!). Any help will be appreciated.

Electrically, this switch is like a momentary switch in
parallel with a regular on/off toggle switch. This is one
option, but more work also.

____|____
| |

---
They're called (are you ready???)

"On - Off - Momentary" toggle switches

http://dkc3.digikey.com/PDF/T052/1207-1211.pdf

 

[Ken Moffett]

I have been looking for a small toggle switch for a test box
that is momentary on, off, and on, but can't find one and
don't know if there is a special name for these switches. I
have seen them, but of course can't find them when needed
(yea, what else is knew!). Any help will be appreciated.

Electrically, this switch is like a momentary switch in
parallel with a regular on/off toggle switch. This is one
option, but more work also.

____|____
| |
---------
M Off On


Dave,

In major electronics catalogs they are usually designated as:

ON-OFF-(ON)

The parinthesies indicates momentary.

But sometimes:

ON-OFF-MOM.

I just went though search for a ON-NONE-(ON), and got a ON-OFF-(ON) by
mistake. Typed in the wrong part number from Mouser. So, I know they have
them.

 

[Neil Kurzman]

In major electronics catalogs they are usually designated as:

ON-OFF-(ON)

The parinthesies indicates momentary.

But sometimes:

ON-OFF-MOM.

I just went though search for a ON-NONE-(ON), and got a ON-OFF-(ON) by
mistake. Typed in the wrong part number from Mouser. So, I know they have
them.

Digikey has them also.
ALCO, C&K and others

 

[[email protected]]

Another odd duck to watch out for is on-on-on.
It's a spdt, but in the middle position, the arm is connected to BOTH
sides. Tough to figure out what's wroing with your creation if you
install one of these by mistake!

 

[jmk]

Another odd duck to watch out for is on-on-on.
It's a spdt, but in the middle position, the arm is connected to BOTH
sides. Tough to figure out what's wroing with your creation if you
install one of these by mistake!

Sounds like the toggle switch equivalent to the old "shorting" rotary
switch, where the next contact makes before the current one breaks.

While we are on the subject, anyone know a source for momentary contact
pushbutton switches. I want one that makes and breaks in one press.
[I.e. press and it makes and breaks the contact, release does nothing
(except re-arm it for the next press). Years ago I took one apart -
basically it's just a little roller under a slider. Goes down one
path, and back up the other. One path it makes contact, the other it
doesn't.

Can't seem to find one in the catalogs now. Just need a modest sized
one that will handle an amp or two. [If I can't find it, I'm going to
have to cobble some circuitry together, in a tight space in the
housing.]
tnx, jmk

 

[Rich Grise]

Sounds like the toggle switch equivalent to the old "shorting" rotary
switch, where the next contact makes before the current one breaks.

I think it's not exactly shorting, but the two sections have different
detent points:

o o o o o o
| | |
o o o o o o
| | |
o o o o o o

While we are on the subject, anyone know a source for momentary contact
pushbutton switches. I want one that makes and breaks in one press.
[I.e. press and it makes and breaks the contact, release does nothing
(except re-arm it for the next press). Years ago I took one apart -
basically it's just a little roller under a slider. Goes down one
path, and back up the other. One path it makes contact, the other it
doesn't.

Actually, it sounds like something's broken. How long of a pulse are
you looking for?

Good Luck!
Rich

 

[jmk]

I think it's not exactly shorting, but the two sections have

different detent points:

You are right, that's different from what I thought was being
described.

Actually, it sounds like something's broken. How long of a pulse
are you looking for?

One man's broken is another man's specification requirement. <G>

These things are mechanical and the pulse length is usually pretty
variable... around 100 ms or so. Unfortunately, my ASCII art isn't as
good as yours, so I hesitate to even try to draw one. They used to be
fairly common, back when "control logic" meant stepper relays and the
like. Now I guess it's so much easier to do everything with
electronics rather than electromechanical, that pulsing a relay
mechanically just isn't much of a market.

jmk