Multiturn pots

Discussion in 'General Electronics Chat' started by R!f@@, Mar 11, 2014.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
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    Sorry about multiple threads. But I think each should have it's own to eliminate problems.

    I am talking about this one.

    It is for the supply I am building.
    I thought using multi turn pots would be better. I needed 4.7K and 10K so I went for 5K instead of 4.7K.

    I can get finer adjustments. Right ?

    Question is these are wire wound and I do not need wire wounds but I do need a knob and to panel mount. I tried to find carbon ones but I can't seem to locate them.

    Are there these type of carbon multi turns ?
    Penal mountable with a knob and all tht.
     
  2. #12

    Expert

    Nov 30, 2010
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    Finer adjustments. Absolutely!

    Don't need wirewound? Are you silly? Carbon elements would never survive in the long run.

    When I was a hot shot, Cermet was the thing. Ceramic metallic elements.

    Cermet and conductive plastic exist in the resistance sizes you named.

    http://www.mouser.com/Passive-Components/Potentiometers-Trimmers-Rheostats/Potentiometers/_/N-9q0yp/
     
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  3. ericgibbs

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    Jan 29, 2010
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    Last edited: Mar 11, 2014
  4. R!f@@

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    Mouser filter comes on when I select what I need.
    And mouser shipping to me was like $75.00 as I recall.

    I am better off Ebay.

    So I should buy them Ebay ones. Don't you think ?
     
  5. #12

    Expert

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    Under $7? That's a good price for this quality.
     
  6. R!f@@

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  7. ericgibbs

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    I was working from your eBay link, quoting Price: US $19.71
     
  8. #12

    Expert

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    You can find whatever bargain you want. I was mostly telling you why you can't find carbon pots. They are not good quality for this application.
     
  9. kubeek

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    Sep 20, 2005
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    Are you really sure you need a mutli-turn pot to do the voltage adjustment? At work I have a 30V 3A lab PSU just with a coarse and fine adjustment and digital readout, and it works just fine. Most of the time I use just the coarse pot, and when doing something more demanding I finetune the value with the fine adjustment pot. I really wouldn't like to turn the knob around ten times to get from 30V to 5V when i swap the device the psu is powering.

    Also, unless you make the supply really stable the output voltage will drift around anyway and I don't think you would ever utlize the "resolution" that the multiturn pot provides. And then there is the price ;)
     
  10. #12

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    Good point, kubeek. Cranking a 10 turn pot does get tiresome.
     
  11. R!f@@

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    Ya ! that was for 5pcs from my cart. :)

    Multi turn pot is what I want in my supply. You have no idea what my supply will have. I don't wanna use two pots each. So using one that will do the trick is better.

    My panel will have 4 voltmeter, 4 Ammeter and 8 VI adjust pots.
     
  12. ericgibbs

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    I wondered why the linked page displayed a price around $6+ for about 1 second, before it changed to $19+...:rolleyes:
     
  13. kubeek

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    Ok I see your point. Will everthing be analog, or will there be some digital controller to it? Because rotary encoders will do the same job but are much cheaper, and could even provide fine adjustment when you turn them slowly and coarser adjustment when you turn them faster, just like on digital scopes.
     
  14. R!f@@

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    Er ! going to digital pot and rotary encoder is out of my league at the moment.
    You missed by EasyPIC thread. I am learning still.

    Besides this one is not a fancy one. Just a heavy duty monster to handle the more demanding needs and it needs to be fixed easily.

    This is the starting journey.

    Will show you when the times comes
     
    Last edited: Mar 12, 2014
  15. strantor

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    Oct 3, 2010
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    Assuming those are not chinese knockoffs, they are good quality pots. Bourns is a good name. I have replaced bourns pots probably 30 or 40 years old, that get turned every day. Took em that long to go bad.
     
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  16. R!f@@

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    It's done..
    Bought 5 pcs pf 5K & 5 pcs of 10K
     
  17. BillB3857

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    Feb 28, 2009
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    If you're looking for fine control, use two pots. Course and fine adjustment.
     
  18. R!f@@

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    Apparently you did not go through the thread :rolleyes:
     
  19. BillB3857

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    Somehow, I did miss during my first read, your statement in post #11 that you did not want two pots. Sorry to have been a bother to you.
     
  20. R!f@@

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    It's cool. No problem mate.
     
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