[Message Prev][Message Next][Thread Prev][Thread Next][Message Index][Thread Index]

Re: End of Line Resistor - Are they a standard design?



"Mike Sokoly" <secure15@xxxxxxxxxxxxx> wrote in message
news:RCe%e.26693$Xa.1009@xxxxxxxxxxx
> Robertm wrote:
>> "Mike Sokoly" <secure15@xxxxxxxxxxxxx> wrote in message
>> news:3lc%e.37805$TA2.1453@xxxxxxxxxxx
>>
>>>
>>>
>>>
>>>
>>>
>>>Crash Gordon wrote:
>>>
>>>>Resistors can be gotten from any electronics supplier. Sometimes you
>>>>can't get the exact spot on value and have to fudge it a bit, but unless
>>>>its a really weird resistor you should be able to find replacement.
>>>>
>>>
>>>Remember that 4th band on the resisitor? Gold/Silver/None?
>>>You can get pretty close, then if your not exact: remember to look at the
>>>tolerance band: +/- 5%, 10%, 20% then do the math- if your intended value
>>>falls within the +/- % spec you're good to go!
>>>Mike S.
>>>
>> I don't think so. If you're looking for a 2K resistor and you find a
>> 2.5K - 20%, it could be anywhere from 2K to 3K. If it's more than 2.3K,
>> you'd be out of spec for many systems. You'd have to actually measure the
>> resistor to see what it's value is. Most resistors on the market today
>> are 5%. Rather than mess with tolerances, you'd be better off combining
>> resistors in a series or parallel configuration to get what you want.
>> Resistors in series add their values Rt = R1 + R2. For resistors in
>> parallel  (R1xR2) / (R1 + R2).
>>
>> Bob
> Most are 5%?"I do'nt think so"- I can find 10% easily.
> Why do you think I said "DO THE MATH"?
> My stupid assumption that guys who install in the field are competent and
> capable as well as maybe having SOME BASIC knowledge( maybe they passed a
> State Test?) SOME Courses go over this!
> What's your're thoughts on matching Wattage, Genius?

Perhaps I misunderstood what you were saying. I thought you were indicating
a 20% resistor would work for any desired value within + or - range because
you didn't make any mention of taking an actual measurement of the resistor
value. Sorry, didn't mean to ruffle your feathers. Yes, I agree you can
still find 20% resistors but they are not as common as 5%. Most carbon film
1/2 watt resistors readily available these days marketed with a 5% tolerance
unless you're shopping from a surplus house or yard sale. What is it that
you want to know about wattage?

bob




alt.security.alarms Main Index | alt.security.alarms Thread Index | alt.security.alarms Home | Archives Home