Advertisement

Electronics and Electrical Engineering Design Forum

Where you can find electronics and electrical engineering forum questions & answers.
no image Wednesday, December 06, 2017 by Andrew Gale

Shorter leads on through-hole resistors?

Hello all, I'm hoping for a bit of advice on through-hole resistors and, specifically, how they supplied on 'bands' (if that's the correct expression?).


I make up quite a lot of small soldering kits for my students and for attendees at soldering workshops at "Raspberry Jams". It might sound trivial but the most annoying components to pack in small plastic bags are the resistors... the ones I buy from Rapid come on bands that are approx 6cm wide.


However, I've noticed that Velleman sell packs of assorted resistors that are on narrower bands - about 4cm wide. I was wondering if anyone had ever seen resistors for sale in bulk on these narrower bands? I'm wondering if Velleman has some way of re-banding components because I've noticed that some of their project kits come with bands containing resistors of different values as required by the project.


Any suggestions/pointers kindly received!


-Andy

Comments

  • by  Alan Winstanley

    Hi Andy

    Resistors are often manufactured and supplied in bandoliers (also called ammo packed), and they're a pain to handle, so I can understand the problem.

    Different manufacturers have their own packaging spec, also it might relate to the size & power rating of resistors. Smaller low power ones might come packaged in narrower bandoliers anyway. Velleman might kit them up in house from bulk (loose) resistors.

    I don't know that there's a simple workaround for what you need, but googling around I see how some hobbyists use home-made workarounds to cut resistors from the bandoliers automatically.

    Personally I think you would need to check out manufacturers' specs, or try larger poly bags? Ebay has loads :)

    -- Alan W
  • by  Andrew Gale

    Thanks, Alan... yes, I suspect the best answer is just to accept that I need bigger bags! I was hoping there might be some ready source of the narrower bandoliered resistors, but perhaps not - the only ones I've ordinarily seen have been the ~6cm ones.

    Thanks for the suggestion about lower-power resistors, I hadn't thought of that (I usually just default to 0.25W) but will look into it.

    All the best,

    Andy
  • by  Mike Anderson

    I've always found that my students either use the legs as is, or they trim them to fit.  So, often while kitting lab set ups, I'll just fold the bandoleer in half and stuff it in the bag/box.  You rarely see resistor leads break under normal use and they're so cheap that I don't lose sleep if a couple of them do break off.  The students are only interested on the color bands and getting them into the protoboard.  You can always use additional jumper wires if the leads are too short.

    HTH,

    Mike

  • by  Rick Curl
    Hi Andy-

    Velleman is using a device known as a "component sequencer" which receives components on multiple taped reels and "sequences" the components onto a new reel.  In the process of doing this it shears off the original tape, plus a bit of the component leads, before re-taping them in their new sequence.

    Here's an example of a Component Sequencer.

    -Rick


  • by  David Ashton
    Interesting stuff.  Andrew, if you had not already gathered, the resistors are in bandoliers for automated component handling machines.

    One reason I don't like them like this is that a little bit of the glue on the tape ends up on the resistor lead, and eventually on your breadboard contacts.  So don't just pull the ends out from the tape, snip them off.  You can do this easily in bulk with a pair of tinsnips or even really stout scissors.  And don't tape them again, your students should do their own component selection and handling!

    A supplier I get resealable bags from does them in 50x75, 75x100, 100x125 mm (2x3, 3x4, 4x5 inches) so even the smallest one will just take a 6cm resistor.  I have bought smaller ones than that.  

    Some years ago I wrote a blog about storing electronic components - the first photo there shows just the thing we are talking about.  You can't get these boxes any more but all sorts of things are available - some with removable dividers so you can tailor the compartments to suit the size of the things you're storing.  Might give you some ideas.  Cheers // David

    • by  Andrew Gale
      Thanks, David... I've just enjoyed going back through some of your blog posts, the one about salvaging parts from PCBs was very nostalgic for me as I used to spend a lot of time desoldering old radios, cassette recorders etc.


      I've often wondered about the sticky residue on the end of resistors - I usually try and smudge it off between my thumb and finger but it can't be good for the breadboard contacts. I'll be sure to trim them off in future!


      -Andy

      • by  David Ashton (edited)

        Andrew... "I've often wondered about the sticky residue on the end of resistors - I usually try and smudge it off between my thumb and finger..."   Rather use methylated spirit (if you're in the US it'd be called something different I think - alcohol of some sort?) on a cloth to wipe it off if you need the long leads for any reason.  Fingers aren't that good!

  • by  Andrew Gale
    Thanks, David... I've just enjoyed going back through some of your blog posts, the one about salvaging parts from PCBs was very nostalgic for me as I used to spend a lot of time desoldering old radios, cassette recorders etc.


    I've often wondered about the sticky residue on the end of resistors - I usually try and smudge it off between my thumb and finger but it can't be good for the breadboard contacts. I'll be sure to trim them off in future!


    -Andy

    • by  David Ashton (edited)

      Andrew... "I've often wondered about the sticky residue on the end of resistors - I usually try and smudge it off between my thumb and finger..."   Rather use methylated spirit (if you're in the US it'd be called something different I think - alcohol of some sort?) on a cloth to wipe it off if you need the long leads for any reason.  Fingers aren't that good!

  • by  David Ashton (edited)

    Andrew... "I've often wondered about the sticky residue on the end of resistors - I usually try and smudge it off between my thumb and finger..."   Rather use methylated spirit (if you're in the US it'd be called something different I think - alcohol of some sort?) on a cloth to wipe it off if you need the long leads for any reason.  Fingers aren't that good!

  • by  Andrew Gale

    Thanks, Mike and Rick.... that Component Sequencer looks like an amazing piece of machinery! It would make a lot of sense for Velleman to use something like that when making their kits - certainly a lot easier that dealing with individual resistors of different values. And it would explain the shorter leads / narrower bandoliers.

    Thanks!

    Andy

Add Comment

You must log-in to comment.