Is there such a thing as a momentary SPDT off-on-on switch? "off-(on)-(on)"

Question

I'm looking for a toggle or slide switch that has an off and two on positions and is spring loaded to automatically return to off, but one of the on positions is past the other one.

So instead of "on-off-on", I want one that is "off-on-on"

Or maybe "off-onA-onB"

And it should be momentary, so maybe that would be "off-(on)-(on)"?

So you push it to the first click to turn on the "onA" circuit, and then can push it further to turn on "onB".

For my application it would be fine if the second load is only an additional "on" (in other words, onA is also still on when we switch to onB), much like a car key ignition.

But if pressure on the switches is released, the switch automatically returns all the way to off.

Anyone know where I can find a switch like this?

Answer 1

Sort of, this kind of switch is commonly used as a shutter release for digital cameras. They are not the old style toggle type but they work more like tactile momentary type and rely on two different pressure levels to operate. A half press is used to activate the auto-focus and then fully pressing it will take the photo.

Questions about where to buy stuff are off topic but hopefully this gives you a starting point.

If you definitely require an old school up-middle-down lever style toggle then you can get units that are user configurable, where you need to open it up and move the contacts and springs to suit your needs. These are expensive of course.

Answer 2

OTTO has a 3 position P2 Pushbutton switch with 2 levels (steps) of momentary switch action plus the rest (off) position that it returns to automatically. P/N is P2-113321. Its about $140.00 and may have a lead time.

Answer 3

The type of switch you are looking for is called a "momentary" switch. They are available in different forms including a 'toggle' (or bat handled) switch, slide switches and even rotary switches (less common). They are available in different sizes too.

You may find that a DPDT (double pole, double throw) momentary (spring loaded) off-on-off may be able to serve your purpose. You can use its two switches-in-one to provide you with an off-on-on type of result.

If you look at the schematic equivalent of a DPDT switch, you will quickly see how to use it in this way...

At least one place to purchase a switch of this type is at Alibaba.com, search for "DPDT momentary toggle switch". They are also available on Amazon.com and most electronic supply houses.

However you can use a standard DPDT (ON) OFF (ON) momentary switch to get what you want, or close to it anyway. This will work IF you can live with the center position as OFF and then use the (left and right) positions as onA and both onA and onB. A DPDT switch is two SPDT switches in the same package. So lets call them switches A and B. If you wire A to provide you with your 'onA' in both the left and right positions, then if you press the switch left or right onA is turned ON, but in the center position it is OFF. Now wire the 'onB' on the B part of the switch in the (right) position only. In doing so, you will have the spring loaded center position of OFF, then the left momentary position of onA and the right momentary position of both onA and onB. :)