I need help naming a type of rotary switch. (If it exists.)

I am looking for a rotary switch with no stopping point, so it would go around and around when turned, repeating each position infinitely.

Do these exist? If so, what are they called so I know what to look for when I try and buy one online?

Thanks in advance!

  • \$\begingroup\$ rotary encoder. \$\endgroup\$ – old_timer Feb 10 '17 at 2:46
  • \$\begingroup\$ Simply look for rotary switches on Digikey or Mouser. \$\endgroup\$ – Jack Creasey Feb 10 '17 at 4:02
  • \$\begingroup\$ @Jack Creasey I did that. However, I don't know what filter keyword to look for, for a "non stop" rotary switch. \$\endgroup\$ – user2636609 Feb 10 '17 at 6:06
  • \$\begingroup\$ @old_timer I purchased a few low priced rotary encoders to experiment with. Thank you. \$\endgroup\$ – user2636609 Feb 10 '17 at 6:08
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    \$\begingroup\$ try 'continuous rotation' as a search term. If you go to CPCFarnell and look at their cheap 12 way single pole switches, these come with a little tab that you can move to restrict their rotation down to the number of ways you want. If you leave that little tab out, they just go round and round. \$\endgroup\$ – Neil_UK Feb 10 '17 at 9:25

A Rotary Encoder

Rotary encoders are used in many applications that require precise shaft unlimited rotation

From Wiki. enter image description here

The picture above depicts the waveforms found at points A and B of encoder. Depending on which signal (A or B) transitions to next state ,the host can detect the direction. Each click or step is called a detent and is a stable position of the encoder.

A normal connection would like this:

R should be sized in 100s of KiloOhm because in stable state, it will be connected between ground and the supply.

Things to look for
Most important things to look in rotary incremental encoder:

  1. Number of detents per 360 degree rotation
  2. Current and voltage rating
  3. the rest such as mounting type, length of shaft etc.
  4. Bouncing time
  5. Min Phase difference between A and B
  6. Additional built in Switch

enter image description here

  • 2
    \$\begingroup\$ A rotary encoder is not a switch. \$\endgroup\$ – Jack Creasey Feb 10 '17 at 4:03
  • \$\begingroup\$ @jack The word 'switch' was supposed to be in line item 2. Typo \$\endgroup\$ – User323693 Feb 10 '17 at 4:05
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    \$\begingroup\$ Still, a rotary encoder is not a switch (whether they encode by physical contacts or quadrature opto's). To use these position encoders takes a lot of external logic. A rotary switch is simply a series of contacts that themselves are the position encoding (if used for that purpose). \$\endgroup\$ – Jack Creasey Feb 10 '17 at 4:10
  • \$\begingroup\$ the only place I used the word switch is in the "things to look for list: Ex.: "both 'switch' and 'encoder' come in one package.. mouser.in/ProductDetail/Bourns/PEC11R-4215K-S0024/… \$\endgroup\$ – User323693 Feb 10 '17 at 4:21
  • \$\begingroup\$ Reading more about rotary encoders, now that I know what they're called, I think I see how they differ from a regular rotary switch. Can't wait to try one. Thank you all for your comments and advice. \$\endgroup\$ – user2636609 Feb 10 '17 at 6:13

On many rotary switches, the stops can be broken or bent off - particularly switches with exposed contact wafers.

With many enclosed rotary switches the end stops are removable pins.

In either case, without the stops, the switches are continuous rotation.


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