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Converting low resistance pot to high resistance ?

Discussion in 'Electronic Repair' started by N Cook, Dec 17, 2006.

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  1. N Cook

    N Cook Guest

    Over the years I've often done the opposite by putting a resistor between
    wiper and low end and another from wiper to high end.
    just in case I've missed something over the years is there a way of say
    converting a 20K pot to a 100K pot, with full range from bottom to top ?
     
  2. Meat Plow

    Meat Plow Guest

    No.
     
  3. Guest

    How can you make a 100k pot when youve got a variable R that only
    covers 20k. The answer is you cant. But there are 2.5 buts:

    1. if its a ganged pot its poss to put the 2 tracks in series, doubling
    R. But you cant then have a tapoff that moves anywhere along that track
    length. However in many apps its ok to use a 2 terminal variable R, so
    this will sometimes do.

    2. You may be able to cut the track width down to increase R. Lot of
    hassle though!

    3. Some ccts can be tweaked so they run happily with a lower value pot.

    But in these days of material overflow, its hard to think of any reason
    to do any of the above now.


    NT
     
  4. Arfa Daily

    Arfa Daily Guest

    Likewise, no.

    Arfa
     
  5. Guest

    or lots of cuts across the track 2/3 of the way on alternate sides will
    convert a straight track into a wiggly hence longer and higher R one.
    All depends if youre in a shop or holed up in pow camp.


    NT
     
  6. Not with only passive components.

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
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  7. C R Briggs

    C R Briggs Guest

    Add 4 off 20K fixed resistors in series, with a shorting switch across
    each (or a rotary selector switch). You should get "steps" of 20K with
    a 20K range adjustment in each step (i.e. 100K variable down to 80K; 80K
    variable down to 60K: 60K variable down to 40K: 40K variable down to 20K
    & 210K variable down to 0).

    --
    Regards,

    C R Briggs.

    Reply to address is munged. To reply, remove surplus spaces from:

    btyguard-dontspam @ yahoo . co . uk
     
  8. C R Briggs

    C R Briggs Guest

    DOH!

    Should of course be:

    i.e. 100K variable down to 80K; 80K variable down to 60K: 60K variable
    down to 40K: 40K variable down to 20K & 20K variable down to 0.

    --
    Regards,

    C R Briggs.

    Reply to address is munged. To reply, remove surplus spaces from:

    btyguard-dontspam @ yahoo . co . uk
     
  9. Guest

    that sounds like a challenge if ever I heard one :)

    Take a 100k resistor, scrape the paint off one side. Cut a hole in the
    track to fit it in, glue it there, and connect the leads to the ends of
    the track. Paint over the remaining track. Now, if its all set up
    right, the 100k R acts as the new track.

    For more, google foxhole.


    NT
     
  10. Not quite what I had in mind. :)

    --- sam | Sci.Electronics.Repair FAQ: http://www.repairfaq.org/
    Repair | Main Table of Contents: http://www.repairfaq.org/REPAIR/
    +Lasers | Sam's Laser FAQ: http://www.repairfaq.org/sam/lasersam.htm
    | Mirror Sites: http://www.repairfaq.org/REPAIR/F_mirror.html

    Important: Anything sent to the email address in the message header above is
    ignored unless my full name AND either lasers or electronics is included in the
    subject line. Or, you can contact me via the Feedback Form in the FAQs.
     
  11. Ken Weitzel

    Ken Weitzel Guest

    Hi...

    OK, another way to do it, then.

    Dis-assemble the control. Attach your meter across the outside
    contacts. With a piece of fine sandpaper start sanding away at
    the track. Stop when the meter says 100k. It may or may not
    be linear, dependent on your sanding abilities.

    Take care.

    Ken
     
  12. Guest

    :)


    NT
     
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