Looking for a pot with 360+ degrees of rotation...

The Vishay 601-1045 Full 360° Smart Position Sensor is something to look at.

Mouser stocks it, you'll have to look to the other distributors (Digikey, Newark, Allied, etc.) to compare prices. Not cheap.

--
Dave M
MasonDG44 at comcast dot net  (Just substitute the appropriate characters in the 
address)

"In theory, there isn't any difference between theory and practice.  In 
practice, there is."  - Yogi Berra

Servo type potentiometers(expensive!!!) can turn endlessly, BUT they loose the track for 2 to 4 degrees. I have also used a long time ago a sine/cosine potentiometer, with two wipers, a plus and minus voltage input, and no break in the outputs. Price of that one was about 200 dollars. Google for "sine cosine potentiometer" (no quotes)

it's sometimes called "rotary encoder" you can find some around 10 euros each mouser, digikey it is ALPS products

there are also the other real rotary potentiometers, out of price in my opinion...

--
Jean-Yves.

I believe that once a long while ago I found some by googling "resolver" with some other appropriate words so that you don't get any of the arbitration resolver hits. I think one of the words was potentiometer or rheostat.

If you only need one or two, you might sally on down to your local aircraft boneyard and find a "vor indicator" that is totally trashed and steal the resolver out of it.

Jim

-- "Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, with chocolate in one hand and wine in the other, loudly proclaiming 'WOO HOO What a Ride!'"

--Unknown

Like they say pots without stops are both expensive and archaic. Today they use encoders and D/A or digital solid state potentiometers

You might try this trick - for a sin/cos 360 pot . . .

You get a linear slide potentiometer and spring load it to return to one extreme of the mechanical travel. You take a round disk of the correct diameter and put a shaft through it somewhere towards the rim (off axis) and attach a knob to it. Turn the knob and the disk is a cam that moves the slide pot's wiper. Mount two slide pots at right angles and you have a sine-cosine pot.

The springs will make the knob return to a position that removes the tension so the springs have to be relatively weak - or you might add some dummy slides/springs 180 degrees out to cancel the spring torque.

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I just read your post again - they do make reasonably priced multiturn linear pots that are designed to be used with turns-counting dials (what you are calling a multiturn knob?)

Ten turn pots are probably most common - but I did manage to find a 4 turn pot for some project long ago (servo feedback pot on a chart recorder)

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I guess you already know that ten-turn pots exist...

Chris

what sort of output do you want from this control?

multi-turn pots are available - they go round 5 or 20 times and then stop and you have to turn the other way. you could use a part of that range maybe.

--

Bye.
   Jasen

Thanks, all, for the input and feedback. I *think* I found what I am looking for at Precision Sales and Equip.

It is a 10K single turn pot with continuous rotation (no end stops.) About $20.00, which I can handle. Will let me use a multi-turn knob I have which also has continuous rotation, going from highest setting back to lowest with an additional micro-turn. Am wanting to use this to control a varactor, which in turn controls my homebrew tunable RF amplifier for listening to Shortwave.

Thanks again for the input and feedback. Though I didn't reply to any individually, I read it all with interest and do appreciate it.

Dave

But where does the "multi-turn knob" knob fit in?

Because the term suggest a counter knob, to keep track of ten turn pots. There's no point in having such a counter, if the pot itself can only make one turn.

On the other hand, it almost sounds like you are mis-calling something. A reduction drive would mean that you would need multiple turns of the knob to move the pot from when end to the other. This is a good thing for tuning. But, a stop-less pot won't give you any more function, other than saving you from having to tune all the way down to the bottom of the band.

If you want multiple turns, which is a good thing for tuning something, you want a ten-turn pot, and a counter dial to keep track of how many times you've turned the knob.

Or, you want a good pot (as in that it's not made sloppilly), and a reduction gear so you get multiple turns of the knob to traverse the band.

Michael

Argh. Sorry. My bad. You are right, what I should be calling the knob is a reduction drive. You turn the nob fifteen times for a single turn of the shaft to which it is attached. That's where the single turn pot comes in. And I wanted it stop-less because that's the way the knob is. It goes from

15.x to 0.x with an additional micro-turn, taking the pot back to 10k and the varactor back to 440 pF (or something like that) which will put me back at the bottom of the band without having to undo all those turns. Does that make sense? I am still something of a newbie at all of this, and often confuse my terminology.

Thanks for mentioning the need for a well-built pot. I will check on that before ordering.

Dave