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Wiring a potentiometer — Parallax Forums

Wiring a potentiometer

henrytjhenrytj Posts: 90
edited 2013-09-10 04:07 in General Discussion
Amoungst some parts which I ordered for my current project is a potentiometer. It has 3 prongs/pins. These are not spaced the same as the holes in my solder-less breadboard, and they seem just a little too wide for the breadboard holes anyway. I am wondering if they are meant for either mounting (putting the prongs through holes in a circuit board and bending, or if some kind of connector to fit onto. There are small holes above the pins/prongs but they are so close to the body that he middle hole doesn't go all the way through, and is blocked by a thin (maybe 1/32 inch) layer of translucent plastic that encases the base of the pot. So in order to use it for soldering, I would have to get out my Dremel tool and drill the hole the rest of the way through the plastic outer coating. I am hoping that the pins/prongs are for a connector so that I don't have to solder wires directly to it.

H.

Comments

  • Duane DegnDuane Degn Posts: 10,588
    edited 2013-09-08 14:45
    There are lots of parts that barely don't work in a breadboard. The parts are generally intended to be soldered into place on a PCB designed to accept the part. Parts often have tabs to help hold them in place. I'd need to see the part of datasheet to know make a guess if they are intended to be bent.

    I'd be reluctant to drill into the case of the pot. I often solder some hookup wire to pins that don't quite fit to make them easier to plug into a breadboard.

    I'm not aware of pots designed to be plugged into sockets though I wouldn't be surprised they exist. I would be surprised if your pots were intended for sockets.

    Do you have a link to the part you're talking about?
  • ercoerco Posts: 20,256
    edited 2013-09-08 17:54
    Some soldering is in order. IMO, perfect app to hack some cheap servo extension cables. Cut off whichever end you like (female in this case) and solder the 3 wires to the pot. Now the 3 male pins plug into your breadboard.

    http://www.ebay.com/itm/UN3F-5X-150mm-RC-Servo-Extension-Cord-Cable-Wire-Lead-for-RC-Car-Helicopter-/271228452856?pt=Radio_Control_Parts_Accessories&hash=item3f2679bff8
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-09-08 19:54
    The best pots I've used for breadboards are the 3362P-1-xxxTLF series from Bourns, which I found out about from this Robot Room article:

    http://www.robotroom.com/Trimpots.html

    There are three views of one in a picture there (down the right side of the second photo).

    Parallax 3 wire connectors are good for connecting pots and other things. I just cut them in half to make two cables with a plug on one end and stripped wire to be soldered on the other.
  • henrytjhenrytj Posts: 90
    edited 2013-09-09 16:12
    Here is the pot in question. See how the plastic cover blocks the middle hole, which might be for soldering. Might the prongs be meant for a connector of sorts? Would be nice to not have to solder. But if I do, solder to pins? or drill out the middle hole?

    Attachment not found.
    Pot-1-IMG_1771-Med.jpg
    Pot-2-IMG_1772-Med.jpg
    Pot-1-IMG_1771-Med.jpg
    964 x 814 - 82K
    Pot-2-IMG_1772-Med.jpg
    742 x 778 - 78K
  • Mike GreenMike Green Posts: 23,101
    edited 2013-09-09 16:31
    That pot is designed to be directly soldered to a PCB with holes with the correct size and spacing.

    I would strip the insulation for 1/4" to 3/8" off the end of a wire and wrap the wire around one of the pins, repeat for the other pins, then solder the wires to the pins.

    Do not drill out the middle hole. It's not necessary.
  • ercoerco Posts: 20,256
    edited 2013-09-09 17:05
    Those holes are rivets/stakes for mechanically holding the metal tabs to the phenolic insulator.

    Per Mike, don't drill them out. Neither necessary nor desirable.
  • henrytjhenrytj Posts: 90
    edited 2013-09-09 17:27
    The possibility that came to mind was not to drill out the rivet itself, but a small bit to just drill through the plastic bottom covering. I haven't tried to see ith maybe the plastic slides off.

    But thanks. I will solder to the pins, or maybe solder to the holes on each side as those are clear, and solder to the middle pin.

    H.
  • RDL2004RDL2004 Posts: 2,554
    edited 2013-09-10 04:07
    That type of pot is meant to be mounted to a panel. That's why it has the threaded collar and nut. In use, wires could be soldered directly to the pins or a specialized push on connector could be used. Sometimes a tiny piece of pc board is used as a go between connection between the wires and the pot. Sometimes the pot will be bolted to a panel and soldered to a pc board at the same time. If the only mechanical connection is by being soldered to a pc board, then the connection will quickly fail due to the pins all being inline. This allows the pot to wiggle back and forth as it's used and the the solder joints will eventually break.
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