[Milsurplus] Carbon Comp Resistors: The Darkness Gathers?

[Richard Solomon]

There is one called Resistor Scanner.

73, Dick, W1KSZ

On Mon, Jul 2, 2018 at 6:06 PM, Peter Gottlieb <kb2vtl at gmail.com> wrote:

> Is there a smartphone app for resistors where it tells you the value based
> on its camera?
>
>
> On 7/2/2018 6:25 PM, Mark K3MSB wrote:
>
>> I've found it's the lower values, typically up to maybe half a meg, that
>> go high with the lower values, say under 100 ohms, to be particularly prone
>> to going out of tolerance.
>>
>> I've about two medium postal boxes of unused carbon comp resistors in the
>> "pile".    Since I'm pretty color-blind the only way I can determine the
>> resistance value is to use a meter, and then I'd have little chance of
>> knowing if it matched the funny colored rings around the body.
>>
>> 73 Mark K3MSB
>>
>> On Mon, Jul 2, 2018 at 4:15 PM, David Stinson <arc5 at ix.netcom.com
>> <mailto:arc5 at ix.netcom.com>> wrote:
>>
>>     I've always heard that the carbon comp resistors
>>     that fail Hi-Z most often are those in the
>>     Mega-Ohm range ("green band").  Oddly, over the
>>     last four major projects:  TCS, ATD, RAX and now
>>     SCR-522, haven't found that to be the case.  The
>>     resistors most often failed-High are in the
>>     15K-500K range, with the #1 "bad guy" being 47K
>>     Ohms, followed by 470K.  I remember changing one
>>     or two Mega-Ohm value resistor in the last three
>>     projects.  Every 47K resistor in the last TCS
>>     receiver and in the ATD had to go.
>>
>>     Which brings me to this:
>>     I've got piles of NOS Carbon Comps that have been
>>     following me around for eons.  The majority of
>>     these have started reading Hi-Z by 5% or more.
>>     Many by much more.  I just threw a half dozen NOS
>>     100K away because they read from 107K- to
>>     122K-Ohms.  Other values are showing similar
>>     drift.
>>
>>     Has twilight come for Carbon Comp resistors?  I've
>>     stopped buying them at hamfests and use only the
>>     newer, ceramic looking thingies for projects now.
>>     What do you think?
>>
>>
>>     GL OM ES 73 DE Dave AB5S
>>
>>
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