Shrinkage...resistors been in the pool?

Started by RedHouse, May 02, 2011, 11:48:47 AM

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RedHouse

Sorry 'bout the Seinfeld ref-joke there but....

I thought I'd take the splash and try ordering some of those quantity package "pick-yer-values" deals I see all the time on eBay out of China.

I got a qty of 2000 of my values for like $35.00 seemed a good deal.

Then when I go to install some the other day I notice the leads seemed really thin/skinny. I went to my misc parts box and dig out some examples and sure enough, these new China resistors have leads like 1/2 the thickness of old USA resistors, and 2/3 of the cheap Xicons you get from Mouser.

Here's a pic:



While this doesn't effect their operation, it does bring up the question of at what point will vibration (loud music, on stage etc) start effecting our builds.

For example with instrument pickups we tend to pot them to keep microphonics down, so when our resistors leads get soo thin they can't hold them still on the PCB and start vibrating we may have to address that in the future of DIY.

Don't they know about shrinkage?

{Edit} the source was www.sun-pec.com and they have an eBay store.

ayayay!

I noticed the same thing.  While it wouldn't bother me that they're so thin, I kind of like the thicker lead for pre-bending.  But, I understand it's about using less material.   :-\
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Processaurus

I have some super el cheapo AA batteries from china that must have been in the same chilly economic pool, they were hilariously about 3/4 the diameter of a Duracell AA.  2x4's used to be 2" by 4"; shrinkage!

Perrow

Quote from: RedHouse on May 02, 2011, 11:48:47 AM
For example with instrument pickups we tend to pot them to keep microphonics down, so when our resistors leads get soo thin they can't hold them still on the PCB and start vibrating we may have to address that in the future of DIY.

You'll know you're buying too cheap parts when your resistors are microphonic  :icon_eek:
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StereoKills

I too got one of the the "El Cheapo" MF resistor packs from Ebay when I first stocked my bench. Have never had any reliability issues with them, but any values I need now I get from Mouser, usually Vishay or KOA Spear. They're pretty inexpensive and are much sturdier.
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petemoore

#5
 Sprung mass is much more reliant on lead strength in bad design points. Large radial capacitors 'mounted' by leads is prime example.
 The tensile strength on these R leads is more than adequate when they are laid down, and if stood up and 'teepee'd' with a third connection, the physical strength of the tripod is also more than sufficient.
 The deflection/bend strength diminishes as the surface cracks appear.
 Most of the tensile strength is had right at the very outside/inside surfaces as determined by the bend/angle.
 In the same way a sharp bend stretches the outside surface [it's distance increases, or the inside surface compresses], of a bent rod if the bend is made sharply, the thicker rod equates to greater stretching of the outside surface for = X bend sharpness. Typical bend may show less cracking on the outside stretch and less 'mountaining' on the inside stretch [lines may appear as the very inside surface 'makes room', in a similar way to tectonics.
 Because R's are so small and light, even standing up the connection leads would be very difficult to destroy by circuit box vibrations.
 I prefer them primarily for 2-leads-in-1 perfboard hole, neater/fewer pads required per circuit, also for general frugality reasons.
 Forbid the mention of tubular wiring, which would really save on the copper.
 Added Microphonics had from mojo-lead resistor makes for an excellent distorter ad feature bulltepoint.
Convention creates following, following creates convention.

RedHouse

Quote from: petemoore on May 03, 2011, 09:11:23 AM
Sprung mass is much more reliant on lead strength in bad design points. Large radial capacitors 'mounted' by leads is prime example.
 The tensile strength on these R leads is more than adequate when they are laid down, and if stood up and 'teepee'd' with a third connection, the physical strength of the tripod is also more than sufficient.
 The deflection/bend strength diminishes as the surface cracks appear.
 Most of the tensile strength is had right at the very outside/inside surfaces as determined by the bend/angle.
 In the same way a sharp bend stretches the outside surface [it's distance increases, or the inside surface compresses], of a bent rod if the bend is made sharply, the thicker rod equates to greater stretching of the outside surface for = X bend sharpness. Typical bend may show less cracking on the outside stretch and less 'mountaining' on the inside stretch [lines may appear as the very inside surface 'makes room', in a similar way to tectonics.
 Because R's are so small and light, even standing up the connection leads would be very difficult to destroy by circuit box vibrations.
 I prefer them primarily for 2-leads-in-1 perfboard hole, neater/fewer pads required per circuit, also for general frugality reasons.
 Forbid the mention of tubular wiring, which would really save on the copper.
 Added Microphonics had from mojo-lead resistor makes for an excellent distorter ad feature bulltepoint.

Whoa, man, you really should change that bong water!    :icon_lol:

g-sus

I've used hundreds of these without problems..cool thing with these is you can fit 2 resistor legs through one vero/perfboard hole ;) (like Petemoore also said earlier)

petemoore

#8
Whoa, man, you really should change that bong water!
  Sorry, I have no bongload for you.
 All you need to know in respect to this thread is that it is reasonable to expect no problems with these resistor leads, thicker lead resistors are available.
  Goodbuy !
Convention creates following, following creates convention.

RedHouse

#9
Quote from: petemoore on May 06, 2011, 08:34:42 AM
Whoa, man, you really should change that bong water!
  Sorry, I have no bongload for you.
 All you need to know in respect to this thread is that it is reasonable to expect no problems with these resistor leads, thicker lead resistors are available.
 Goodbuy !

I was just kidding about the bongwater dude, lighten up.  :icon_biggrin:

My OP was a heads-up, not a question, but thanks for that though.

I was making the point that leads are getting overly flimsy ...from certain sources... some are approaching a point where we might need to start considering them as a source of problems.

PRR

> 2x4's used to be 2" by 4"; shrinkage!

The lumber was never 2x4... the saw was set on 2" or 4" increments, the wood was thinner by the width of the blade. On large old circular-saws this could be a lot thinner. And rough. Planed wood is nicer to handle. A S4S stud would never be over 1.75x3.75, often 1.625x3.625 (which was standard mid-20th-century).

1-5/8 is an odd size to compute in your head. Also lumber got better: far fewer really bad chunks. In the 1960s lumber changed to 1.5"x3.5" S4S with grade-stamp. They say it is as strong as the old rough-sawn. IMHO it is. I have large lumber milled on this site, and I use it to match the framing in this house. But I have to go over every piece for funky grain and splits and punk. If size-match is not an issue, I use commodity 1.5x3.5 stuff: it warps and is cheezy, but it is uniformly cheezy, no funky punky wood from infested trees.

And what Pete said is all on-target.
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