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Science Forum Index » Electronics - Basics Forum » Resistor power rating
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| galapogos |
 Posted: Wed Jan 31, 2007 11:52 am |
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Hi,
I'm wondering if there's some sort of a chart or reference to find out
what kinda package is needed for what kind of power rating for SMT
ceramic resistors. I have a design where I need a 0ohm resistor that
passes up to 2A @5VDC. Would a 1206 size be sufficient?
Thanks. |
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| John Popelish |
| Posted: Wed Jan 31, 2007 12:10 pm |
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Guest
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galapogos wrote:
Quote: Hi,
I'm wondering if there's some sort of a chart or reference to find out
what kinda package is needed for what kind of power rating for SMT
ceramic resistors. I have a design where I need a 0ohm resistor that
passes up to 2A @5VDC. Would a 1206 size be sufficient?
You mention power rating and current. If a resistor is
really zero ohms, it doesn't dissipate power, regardless of
the current. Of course, no room temperature superconductors
are yet available, so any real resistor will have some
resistance, even if it is sold as a zero ohm device. You
really have to go to the data sheet and see what its current
rating is, but I am pretty confident that a 1206 zero ohm
jumper would be fine carrying 2 amperes. |
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| tlbs101 |
| Posted: Wed Jan 31, 2007 3:05 pm |
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On Jan 31, 8:52 am, "galapogos" <gois...@gmail.com> wrote:
Quote: Hi,
I'm wondering if there's some sort of a chart or reference to find out
what kinda package is needed for what kind of power rating for SMT
ceramic resistors. I have a design where I need a 0ohm resistor that
passes up to 2A @5VDC. Would a 1206 size be sufficient?
Thanks.
Most zero-Ohm resistors I have seen are sub-100 milliOhm, nominally
between 10 and 50 milliOhm. Even in absolute worst-case if one of
them happened to come up 100 mOhm, I^2*R loss would only be 0.4 W and
the 1206 package can take that for a short while.
A much more likely worst-case scenario would be 50 mOhm, which would
disspilate less than 0.2W, for which the 1206 is generally rated.
Check the manufacturer's data sheet for their zero-Ohm parts. That
will usually tell you what the nominal and max. "zero Ohm" resistance
really is.
Tom P. |
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| galapogos |
| Posted: Wed Jan 31, 2007 9:04 pm |
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Guest
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On Feb 1, 12:10 am, John Popelish <jpopel...@rica.net> wrote:
Quote: galapogos wrote:
Hi,
I'm wondering if there's some sort of a chart or reference to find out
what kinda package is needed for what kind of power rating for SMT
ceramic resistors. I have a design where I need a 0ohm resistor that
passes up to 2A @5VDC. Would a 1206 size be sufficient?
You mention power rating and current. If a resistor is
really zero ohms, it doesn't dissipate power, regardless of
the current. Of course, no room temperature superconductors
are yet available, so any real resistor will have some
resistance, even if it is sold as a zero ohm device. You
really have to go to the data sheet and see what its current
rating is, but I am pretty confident that a 1206 zero ohm
jumper would be fine carrying 2 amperes.
Thanks! |
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| John Popelish |
| Posted: Wed Jan 31, 2007 9:23 pm |
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Guest
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galapogos wrote:
Quote: On Feb 1, 12:10 am, John Popelish <jpopel...@rica.net> wrote:
galapogos wrote:
Hi,
I'm wondering if there's some sort of a chart or reference to find out
what kinda package is needed for what kind of power rating for SMT
ceramic resistors. I have a design where I need a 0ohm resistor that
passes up to 2A @5VDC. Would a 1206 size be sufficient?
You mention power rating and current. If a resistor is
really zero ohms, it doesn't dissipate power, regardless of
the current. Of course, no room temperature superconductors
are yet available, so any real resistor will have some
resistance, even if it is sold as a zero ohm device. You
really have to go to the data sheet and see what its current
rating is, but I am pretty confident that a 1206 zero ohm
jumper would be fine carrying 2 amperes.
Thanks!
What weight and width of copper traces are you using to
carry this 2 ampere current? |
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| galapogos |
| Posted: Wed Jan 31, 2007 10:27 pm |
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Guest
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On Feb 1, 9:23 am, John Popelish <jpopel...@rica.net> wrote:
Quote: galapogos wrote:
On Feb 1, 12:10 am, John Popelish <jpopel...@rica.net> wrote:
galapogos wrote:
Hi,
I'm wondering if there's some sort of a chart or reference to find out
what kinda package is needed for what kind of power rating for SMT
ceramic resistors. I have a design where I need a 0ohm resistor that
passes up to 2A @5VDC. Would a 1206 size be sufficient?
You mention power rating and current. If a resistor is
really zero ohms, it doesn't dissipate power, regardless of
the current. Of course, no room temperature superconductors
are yet available, so any real resistor will have some
resistance, even if it is sold as a zero ohm device. You
really have to go to the data sheet and see what its current
rating is, but I am pretty confident that a 1206 zero ohm
jumper would be fine carrying 2 amperes.
Thanks!
What weight and width of copper traces are you using to
carry this 2 ampere current?
Actually it's not really 2A. 2A is the upper limit. I'm probably
expecting something to the order of 1A or less typical. |
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