EOL's

[Chub]

youstarted it with your "responsible comments requested". What did you
expect?

OK!!! OK!! Ok!

As the Original Poster on this topic I was hoping that this would have
been simple calm discussion.
But NOOOOO!!

You guys amaze me to no end. Therefore I did what I was trying to avoid
and did a Google search to try and find the answer to my question. After
searching on [resistor value tolerance] I received 446,000 hits. I did
not read them all, nor did I find my answer, but I did find some
supporting information on both sides of the fence. Could it be that
everybody is RIGHT????

I have included some of my findings below. You can all read to your
hearts content and try and find the part that may support your own special
thoughts.

Personally I am moving on to more important issues of the day, like What's
for Lunch.

Please find some of the research below.

Have a nice day and a better tomorrow.

Les

==========================================================================
http://en.wikipedia.org/wiki/Tolerance_(engineering)
Tolerance (engineering)
From Wikipedia, the free encyclopedia
Jump to: navigation, search
Tolerance in engineering is an allowance, given as a permissible range, in
the nominal dimension or value specification of a manufactured object. The
purpose of a tolerance is to specify the allowed leeway for imperfections
in manufacturing the part or component.

The tolerance may be specified as a factor or percentage of the nominal
value, a maximum deviation from a nominal value, an explicit range of
allowed values, be specified by a note or published standard with this
information, or be implied by the numeric accuracy of the nominal value.
Tolerance can be symmetrical, as in 40±0.1, or asymmetrical, such as
40+0.2/-0.1.

It is good engineering practice to specify the largest possible tolerance
while maintaining proper functionality, since closer or tighter tolerances
are more difficult to manufacture and hence cost more to either build or
buy.

Tolerance is different from safety factor, but an adequate safety factor
will take into account relevant tolerances as well as other possible
variations.

[edit]
Electrical component tolerance
An electrical specification might call for a resistor with a nominal value
of 100? (ohms), but will also state a tolerance such as "±1%". This means
that any resistor with a value in the range 99? to 101? is acceptable. It
would not be reasonable to specify a resistor with a value of exactly 100?
in any case, because the exact resistance will vary with temperature,
current and other factors beyond the control of the designer.


http://www.southwest.com.au/~jfuller/electronics/resistors.htm
Resistors are constructed to provide predetermined resistances. Most
common resistors are guaranteed to be within 5% of their marked value.
('Metal-oxide' resistors with a blue body are guaranteed to meet their
marked value plus, or minus 1%.)


http://www.tpub.com/neets/book1/chapter1/1q.htm
Although you may find any of the above colors in the third band, red,
orange, and yellow are the most common. In some cases, the third band will
be silver or gold. You multiply the first two bands by 0.01 if it is
silver, and 0.1 if it is gold. The fourth band, which is the tolerance
band, usually does not present too much of a problem. If there is no
fourth band, the resistor has a 20-percent tolerance; a silver fourth band
indicates a 10-percent tolerance; and a gold fourth band indicates a
5-percent tolerance. Resistors that conform to military specifications
have a fifth band. The fifth band indicates the reliability level per
1,000 hours of operation.


http://www.mycableshop.com/techarticles/ResCodes.htm
Resistors come in standard values such as 1K, 2.2K, 4.7K, and so on. Why
these values? Consider a range of resistors with a 10% tolerance. The
resistors are designed with values such that a 10% variance of one
resistor would meet or overlap with the 10% variance of the next
resistance value.

To clarify, the 10% tolerance range for a 1K resistor would be 0.9K to
1.1K. So the next resistor value going up the scale would be 1.2K since
it's 10% tolerance range would be 1.08K to 1.32K. The lower end of the
tolerance range for the 1.2K overlaps a little with the upper end of the
range for the 1K.

In the case of a range of resistors with a 5% tolerance, there would have
to be more unique values to allow for overlap. Starting with the 1K
resistor, the next resistor value up the scale would have to be 1.1K to
allow for an overlap. Resistors with a 20% tolerance on the other hand
would have bigger jumps between values. Starting with the 1K resistor,
the next value up the scale would be 1.5K. In this case, the upper value
for a 1K would be 1.2K, while the lower value for a 1.5K would be 1.2K.



http://en.wikipedia.org/wiki/Resistor
Preferred values
Standard resistors are manufactured in values from a few milliohms to
about a gigohm; only a limited range of values called preferred values are
available. In practice, the discrete component sold as a "resistor" is not
a perfect resistance, as defined above. Resistors are often marked with
their tolerance (maximum expected variation from the marked resistance).
On color coded resistors the color of the rightmost band denotes the
tolerance:

silver 10%
gold 5%
red 2%
brown 1%.
Closer tolerance resistors, called precision resistors, are also
available.

[edit]
5-band axial resistors
5-band identification is used for higher tolerance resistors (1%, 0.5%,
0.25%, 0.1%), to notate the extra digit. The first three bands represent
the significant digits, the fourth is the multiplier, and the fifth is the
tolerance. 5-band standard tolerance resistors are sometimes encountered,
generally on older or specialized resistors. They can be identified by
noting a standard tolerance color in the 4th band. The 5th band in this
case is the temperature coefficient.

http://www.electronic-circuits-diagrams.com/tutorials/resistors.shtml
Tolerance is the extent to which the resistor value sways from the
original value. You may think as to why the resistance value should change
from the printed value? Well, we live in a world that is far from perfect
and resistors are no exceptions. Their value changes mainly due to the
change in temperature.

 

[Al Colombo]

73's, Russ!!

 

[Al Colombo]

Not sure where it came from, other than in my day, we used it all the
time, but I'll bet it has something to do with a bad card in poker

Al

 

[ABLE_1]

This is to answer a number of questions or comments in one post.

youstarted it with your "responsible comments requested". What did you
expect?

The truth be told, it would not have matter if I would have placed the
"responsible comments requested" line in or not. The thread would have
reached the same this same point in time anyhow. I was just hoping
otherwise.

===================================================

Is this in a commercial structure where there is lots of metal?
Second, is the switch part of an opening that is rarely used?

Al

This is a normal commercial structure office environment built in maybe the
70's and the switch is on the Entry/Exit door which is used constantly
through out the day.

===================================================

Earlier I may have mis-spoken when I said that "I thought the resistor was
at 10% tolerance" After some thinking in my minds eye it would have been
better to say either a 5% or 2% would be more likely.

I also stated that the value changed some 56.7% higher. Well outside the
normal tolerance expected. And that nothing looked unusual about the
resistors condition.

I still don't have an answer only assumptions. But that's ok. I had my
lunch and now on to other things.

Les

 

[Al Colombo]

My thinking was that if you open the door and the panel says it's not
open, even if the resistor were 5 times higher than normal, the panel
would have to show an open, unless 1) the switch contacts were stuck
together, which can happen when it is a mag reed and it sits for
prolonged periods without being used, or 2) the EOL is on the positive
side of the switch in the circuit and even a single strand of wire is
touching earth ground on the positive side of the switch.

The latter situation would essentially route the supervisory current
directly from the negative side of the initiating circuit (panel
ground) through the earth ground connection through the EOL and on to
the positive side of the initiating circuit, thus completing the
circuit.

Just a thought. But the resistor alone in this case should not have
caused the panel to indicate a closed circuit when the door was in an
open state, that is if I understand your situation correctly. I think
there's another issue here and not just the EOL, what do you think?

If a strand of wire were out of place, and if the EOL were on the wrong
side ot the switch, this scenario could occur. Now, once you began
working on the door switch and EOL, you could possibly move the single
strand of wire away from the metal door frame so the earth ground
connection disappeared. You do have the EOL at the door switch and not
inside the can, right?

I'd check to see if the EOL is on the positive or negative side of the
resistor. If you find that it's on the negative side, then the
scenario I just outlined would be invalid. On the other hand, if you
do find the EOL is on the wrong side of the circuit, I'd move it to the
negative side.where most manufacturers most often show it, unless it's
a dual-EOL initiating circuit.

Al

 

[Robert L Bass]

How much experience do you really have at servicing electronic systems

Obviously more than you, Al. I spent 24 years actually doing
this for a living while you spent your time asking professionals
(you know, guys like me) to write about it. You then incorporate
the things those of us who know how to install write into
articles in SDM.

Robert? I was trained as an associate engineer in electronics...

Clearly you missed class the day they explained how resistors
function.

the man between the engineers and the manufacturing floor.

I thought that was the janitor's location.

My experience also includes...
--- snip resume ---

I really don't care where you went to school or what you did
before you started writing articles for SDM. You're wrong about
resistor tolerance. Deal with it and move on.

Your assessment of the "resistor" is not practical but
rather theoretical...

My statement was factual, plain and simple. You surmised how
they work and you were wrong. I know how they work. Get over
it. You're only making yourself look foolish trying to argue
this.

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

 

[Robert L Bass]

I know he is trying very hard to yank my chain...

Wrong again, Al. I simply explained the facts. That you
happened to be wrong was incidental.

Back in the 90s I had asked him to do a sidebar on
power supplies for one of my technical stories when
I was with SDM Magazine. He said he would do it
and so I continued on my other work....

Wrong again, Al. You asked me to write the story and I said I
would try to find time. I called and left a message saying I
could not do so because I had to leave due to a family emergency.

--- snip flat out lie ---

I know you like to come across as more knowledgeable than you
are, Al. That's no problem as long as you don't mind being
corrected when you post errors (apparently you *do* mind -- oh,
well). However, the part I snipped was a blatant lie on your
part. You made up that "conversation". It never happened. I
would have been glad to write your article for you at the time
but unfortunately I could not. I tried to notify you. Whether
you got the message in time or not I don't know but the comments
you have made here are simply lies.

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

 

[Robert L Bass]

I don't mean to belittle you as you are obviously trying to do to me,

No, Al. I tried to explain politely why you are wrong. If you
consider that belittling, you've got a problem.

but you really show how little practical field or
bench repair experience you have when you say
that high temperatures, combined with high
humidity cannot affect resistance in a carbon
resistor.

Speaking of journalistic integrity (or lack thereof), that is
*not* what I said. I said that the temperature required to cause
such a significant change in the resistor's value would be enough
to ignite the house. I did not say that high temps and humidity
can't affect carbon film resistors. I did however point out that
the resistors are sealed make humidity a non-issue.

Although it may not be common for a field resistor
to change value based on high ambient heat and
high levels of humidity, it can and does happen in
the real world...

Not with the temperatures in a homes environment (unless you plan
to install the thing in the oven).

To tell anyone that this is not so is doing them a
disservice...

Actually, when you offered advice as to the cause without
understanding you did a disservice to everyone who reads this
newsgroup.

Also, perhaps this man's resistor suffered an induced
high current due to a nearby lighting strike, in which
case the excessive heat caused by the high current
could have super heated the carbon, causing its
properties to change.

Uh-huh. If that had happened there would have been much more
damage to the system than a changed resistor value. A lightning
hit that created that much heat would have blown the sensor to
Waco. Have you ever noticed how fragile magnetic contacts are
compared to a resistor?

What I've told him I stand behind from both my electronic
training and my experience in the field...
--- snip resume ---

Stand wherever you like. You're still wrong about resistor
tolerance. It does not mean what you said and switching to a
closer tolerance resistor would not protect against a recurrence.

I stand behind my statement 100% unless someone
else who has some real engineering knowledge can
step up and refer me to an on-line source of information
that says, as you have, that temperature and humidity,
combined with time, cannot change the value of a
carbon resistor.

That is not what I said. Stop trying to twist my statement into
something you can challenge. It makes you appear olsonic. I
merely corrected your error when you insisted that the resistor
tolerance indicates a propensity of the resistor to change over
time. It means nothing of the sort.

I also explained another fact of which you seem blissfully
unaware. Heat and current sufficient to significantly alter the
resistor's value would be enough to start a fire. The presence
of that much heat would be very apparent -- melted insulation,
vaporized of frozen magnetic contacts, etc.

That's my final word until that day comes.

That day was yesterday. Feel free to continue waiting for its
arrival.

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

 

[Robert L Bass]

My thinking was that if you open the door and the panel says it's not

open, even if the resistor were 5 times higher than normal...

In that case your thinking would be wrong, Al. If the resistor
is 5 times what the panel requires and the panel is programmed to
expect an EOL resistor, the zone will show open.

The latter situation would essentially route the supervisory...
--- snip Rube Goldberg diagram ---

No matter how the circuit was connected, if the resistor was 5x
normal or only 50% higher than normal as in the OP's post, the
panel should show a faulted zone.

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

 

[Al Colombo]

You really are a sad little man, just as all of these folks have been
saying.

Al

 

[Al Colombo]

You are a sad little man, Robert.

 

[Al Colombo]

Wrong again, Al. You asked me to write the story and I said I

would try to find time.

Ha, no one at SDM would ever have asked you to write a story for them,
least of all myself. Don't flatter yourself, you were only asked to do
a short sidebar and you know it. From what I've read here in this
thread, you don't have the technical know how. You did not do the
sidebar because you don't have the knowledge to do it. If you had 24
years of experience before I got into the business in 1974, it sure
doesn't show by your pie-in-the-sky statement about EOLs never changing
their value. That is one of the most silly things I have ever heard.

You made up that "conversation". It never happened. I
would have been glad to write your article for you at the time
but unfortunately I could not. I tried to notify you. Whether
you got the message in time or not I don't know but the comments
you have made here are simply lies.

Right, and pigs fly for sure. Those who have known me for a long time
know this story well. I rule the day I ever asked you to do that
sidebar because ever since then you have dogged my every movement in
this news group. Everything these fellows say about you is evidently
true.

Tell you what, I challenge you to find ONE person who has ever written
ANY story for me and I put my name on it. Go ahead Robert, find
someone and present them to this news group. You won't be able to do
that. You may find plenty of people I've quoted, you may find one or
two that I have given a chance to gain exposure by writing a short
sidebar, but you will not find one person who ever wrote a story for me
and I put my name on it as if I wrote it. I always give people who
help me credit for what they do.

Now, you can chat with Ron Nelson at SDM and I'm sure he'll tell you
that I managed his work, reviewed and edited his stories for many
years, you can talk with Brad Shipp and he'll be able to tell you the
same, or Jim Kelly, and each of them had their byline on what they
wrote. No, you will not find anyone who has ever written a story for
me and SDM, or now SSI put my name on it. That is the most silly thing
I have ever heard. You should stand back and listen to yourself.

You are a sad little man, Robert and I'm not going to waste any more of
my time bantering back and forth with you. You can say what you will.


Al

 

[alarman]

You are a sad little man, Robert and I'm not going to waste any more of
my time bantering back and forth with you. You can say what you will.

Wise policy, Al. You can not win an argument with a fool.
js

 

[Robert L Bass]

You are a sad little man, Robert.

Taking prose lessons from the fellow with the donuts, are you?

--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

 

[Robert L Bass]

Ha, no one at SDM would ever have asked you to write a story for them,
least of all myself. Don't flatter yourself, you were only asked to do
a short sidebar and you know it.

Virtually everything you have written for years has been a
collection of things others in the trade wrote for you. That's
your stock method. Everyone knows it. There's nothing wrong
with that, Al. It's called "reporting" but it does not make you
an expert -- only a reporter.

From what I've read here in this thread, you don't
have the technical know how...

You're the one who came to me asking for help. Saying you were
only doing so to give me "exposure" in a magazine that is only
read by competitors is less than honest, Al.

You did not do the sidebar because you don't have
the knowledge to do it...

And yet you needed my help. Interesting.

If you had 24 years of experience before I got into
the business in 1974, it sure doesn't show by your
pie-in-the-sky statement about EOLs never changing
their value...

Again you're misquoting me. Since I've pointed this out several
times already I can only assume you are doing so deliberately.
What was that you were saying about journalistic integrity?

That is one of the most silly things I have ever heard.

You're the one who said it. Rear my post. That is clearly not
what I said.

Right, and pigs fly for sure...

Perhaps in your mind they do.

Those who have known me for a long time
know this story well...

Correction: Those who have heard you repeat the same lie more
than once might believe it. That doesn't change the fact that
it's a lie.

I rule the day I ever asked you to do that sidebar...

I think you mean "rue the day." Rue is a word meaning regret.
Malapropism is another word with which you should familiarize
yourself. :^)

But I digress. You asked for my assistance because you needed
help. I told you I'd do it if I could find the time.
Unfortunately, circumstances did not permit. Don't make the
mistake of assuming that had anything to do with my diminishing
respect for you as an author or as a human being. You have been
the author of that, unlike most of the things in your column.

because ever since then you have dogged my every
movement in this news group...

No, Al. I have mostly ignored your posts. Most of the threads
you start begin with, "I'm doing an article on [whatever]. Would
anyone here like to write about their experiences with
[whatever]. Those posts, wherein you solicit others to do the
work, are of no interest to me so I usually ignore them.

Sometimes you post good advice. When you do there's nothing to
comment on. Other times (like in this thread) you make incorrect
statements. When I feel inclined to do so I correct you. To
date you've never acknowledged a mistake, though you've certainly
made some. That, along with the personal insults you post in
response to disagreement, is indicative of a very weak ego.
Perhaps you're not so sure of your credentials as you'd like
folks to believe. What kind of engineering degree was it you
claim to have achieved? An "engineer's assistant?" Is that
anything like a dental assistant -- someone who hands tools to
the professional but is not allowed to use them?

Everything these fellows say about you is evidently true.

Perhaps. Perhaps not. None of these fellows has ever met me,
except for one.

Tell you what, I challenge you to find ONE person who
has ever written ANY story for me and I put my name
on it. Go ahead Robert, find someone and present them
to this news group...

Most of your articles are nothing more than quotes of what others
have said or written for you. I'm in Brazil for Carnaval at the
moment and my collection of SDM isn't with me. If I think of it
when I get home I'll be delighted to accommodate you.

You won't be able to do that. You may find plenty of
people I've quoted, you may find one or two that I
have given a chance to gain exposure by writing a short
sidebar...

Heh, heh, heh. One or two? :^)

but you will not find one person who ever wrote a story
for me and I put my name on it as if I wrote it. I always
give people who help me credit for what they do...

I never said you didn't. It is you who have tried to
mischaracterize the level of help you seek from industry
professionals.

Now, you can chat with Ron Nelson at SDM and I'm
sure he'll tell you that I managed his work, reviewed
and edited his stories for many years, you can talk
with Brad Shipp and he'll be able to tell you the same,
or Jim Kelly, and each of them had their byline on
what they wrote...

Ron Nelson is a fine guy. I always liked him. I've met Brad a
couple of times though I doubt he would recall (I'm not all that
impressive )

Never met Jim Kelly. The fact that you worked with them at a
magazine doesn't make you any better or worse. Nice job of name
dropping, though.

No, you will not find anyone who has ever written a
story for me and SDM, or now SSI put my name on it.

The move to SSI was IMO a mistake. SDM, while obviously an
industry advertising-funded trade rag, has always been head and
shoulders better than SSI.

That is the most silly thing I have ever heard.
You should stand back and listen to yourself.

Um, USENET is a text medium. Do you hear the messages here?

You are a sad little man, Robert...

Actually, I'm quite happy and (while nowhere near your girth)
most folks would not consider me little. :^)

and I'm not going to waste any more of my time bantering
back and forth with you. You can say what you will.

You said the same thing several messages ago. Yet here you are.


--

Regards,
Robert L Bass

Bass Burglar Alarms
The Online DIY Store
http://www.BassBurglarAlarms.com

 

[Nick Markowitz]

Looks like Robert is up to his old stunts again so here is my 2 cents worth
with 25+ years of residential and commercail low voltage alarm and high
voltage 120 to 480 volts 3 phase work with resistors.Plus working as a
broadcast engineer at a 5000watt AM station.

I have seen the 2.2 k resistors on FBII equiptment go low
around 1500 ohms on 12 different ocasions due to power surges and
enviromental conditions and I have seen circuits with end line resistors
get tricked in metal buildings when the positive makes ground even with the
resistor in proper place the door was able to be opened and no reaction from
the panel. Saw this happen with the old class A type loops with Holmes
Direct Wire equiptment which is why we never put the switches in the
posistive loop and in the olden days we ran the ground side of the alarm
circuit loop thru a copper water pipe in a building to detect circuit
tampering. or accidental circuit grounds.which was a requirement for UL burg
systems back then.
As far as resistors going high have only seen this 3 times and again
enviromental problems caused it when the resistors material deteriorated.
All electronic components eventually dry up and go bad thats why they say 10
years on most items made these days.Yes I have a 45 + year old radios down
stairs which still fire on but they are the exception not the rule.
The resistors made today are much higher quality than old days but they can
and do drift under the right conditions.
even the 5% tollarance ones.

 

[Chub]

Not sure where it came from, other than in my day, we used it all the
time, but I'll bet it has something to do with a bad card in poker

Googled it and came up with someone being called a 'joker'.
Later morphed into card, I guess.

 

[Crash Gordon]

http://www.bartleby.com/81/3046.html



|
| | > Not sure where it came from, other than in my day, we used it all the
| > time, but I'll bet it has something to do with a bad card in poker
| >
|
| Googled it and came up with someone being called a 'joker'.
| Later morphed into card, I guess.
|
|
|

 

[Crash Gordon]

wha no 88's?


| 73's, Russ!!
|
|
|
| ---
| www.KC80CV.com
|
|

 

[Michael Baker]

73's ?? 'splain ricky.