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Sci.Electronics.Basics -> Regular resistor VS sense resistor
There are 17 messages in this thread.
You are currently looking at messages 1 to 17.
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Author: Kris KriegerDate: 19:35 14-07-08
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If a circuit just calls for something like a 1 Ohm resistor, with no other
info, would it be bad to use a Current Sensing resistor there?
What would be the best way to approach looking up one to get, when no other
info is oprovided at to type or brand?
TIA!
- Kris
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Author: CharlesDate: 19:40 14-07-08
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"Kris Krieger" <me@dowmuff.in> wrote in message
news:rq6dnR0N359Of-bVnZ2dnUVZ_rLinZ2d@earthlink.com...
> If a circuit just calls for something like a 1 Ohm resistor, with no other
> info, would it be bad to use a Current Sensing resistor there?
>
> What would be the best way to approach looking up one to get, when no
> other
> info is oprovided at to type or brand?
Ohm's Law is mostly used to select current sensing resistors.
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Author: Sjouke BurryDate: 19:41 14-07-08
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Kris Krieger wrote:
> If a circuit just calls for something like a 1 Ohm resistor, with no other
> info, would it be bad to use a Current Sensing resistor there?
>
> What would be the best way to approach looking up one to get, when no other
> info is oprovided at to type or brand?
>
> TIA!
>
> - Kris
Pick the most stable one, like the current sense resistor.
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Author: Phil AllisonDate: 19:43 14-07-08
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"Kris Krieger"
>
> If a circuit just calls for something like a 1 Ohm resistor, with no other
> info,
** The fact there IS a circuit plus YOU know its purpose gives you the
other info.
... Phil
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Author: Martin RiddleDate: 20:02 14-07-08
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"Kris Krieger" <me@dowmuff.in> wrote in message
news:rq6dnR0N359Of-bVnZ2dnUVZ_rLinZ2d@earthlink.com...
| If a circuit just calls for something like a 1 Ohm resistor, with no other
| info, would it be bad to use a Current Sensing resistor there?
|
| What would be the best way to approach looking up one to get, when no other
| info is oprovided at to type or brand?
|
| TIA!
|
| - Kris
Pick a resistor that can handle the power, this usually turns out to be a 'Current Sense
Resistor' or "Current shunt" if its
more than a watt or 2. They are more stable over temperature. But if thats not important
in your circuit then a metal film at
the proper rating would do.
Cheers
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Author: Kris KriegerDate: 21:43 14-07-08
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"Martin Riddle" <martin_rid@verizon.net> wrote in
news:5ORek.322$jS4.114@trnddc07:
>
> "Kris Krieger" <me@dowmuff.in> wrote in message
> news:rq6dnR0N359Of-bVnZ2dnUVZ_rLinZ2d@earthlink.com...
>| If a circuit just calls for something like a 1 Ohm resistor, with no
>| other info, would it be bad to use a Current Sensing resistor there?
>|
>| What would be the best way to approach looking up one to get, when no
>| other info is oprovided at to type or brand?
>|
>| TIA!
>|
>| - Kris
>
> Pick a resistor that can handle the power, this usually turns out to
> be a 'Current Sense Resistor' or "Current shunt" if its more than a
> watt or 2. They are more stable over temperature. But if thats not
> important in your circuit then a metal film at the proper rating would
> do.
>
> Cheers
>
>
OK, that helps, thanks!
- Kris
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Author: Kris KriegerDate: 21:44 14-07-08
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Sjouke Burry <burrynulnulfour@ppllaanneett.nnlll> wrote in
news:487be423$0$6026$ba620dc5@text.nova.planet.nl:
> Kris Krieger wrote:
>> If a circuit just calls for something like a 1 Ohm resistor, with no
>> other info, would it be bad to use a Current Sensing resistor there?
>>
>> What would be the best way to approach looking up one to get, when no
>> other info is oprovided at to type or brand?
>>
>> TIA!
>>
>> - Kris
> Pick the most stable one, like the current sense resistor.
THat's helpfult, thanks!
- Kris
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Author: EeyoreDate: 05:43 15-07-08
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Kris Krieger wrote:
> If a circuit just calls for something like a 1 Ohm resistor, with no other
> info, would it be bad to use a Current Sensing resistor there?
>
> What would be the best way to approach looking up one to get, when no other
> info is oprovided at to type or brand?
Normally one would infer type (such as say wirewound if it has to pass a high
current ) from the context of the circuit.
All resisors are 'current sensing' so to speak.
Graham
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Author: Rich GriseDate: 13:05 15-07-08
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On Mon, 14 Jul 2008 18:35:12 -0500, Kris Krieger wrote:
> If a circuit just calls for something like a 1 Ohm resistor, with no other
> info, would it be bad to use a Current Sensing resistor there?
Not at all - that's exactly how it's done.
>
> What would be the best way to approach looking up one to get, when no
> other info is oprovided at to type or brand?
Well, one ohm gives you one volt per amp, so it has to dissipate V * I
watts - if you're sensing 5 amps, which is 5v across a 1 ohm resistor,
that's 25 watts!
And, the precision of your measurement will depend on the precision
of the resistor.
Good Luck!
Rich
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Author: Kris KriegerDate: 13:19 15-07-08
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Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote in
news:487C713A.7263578D@hotmail.com:
>
>
> Kris Krieger wrote:
>
>> If a circuit just calls for something like a 1 Ohm resistor, with no
>> other info, would it be bad to use a Current Sensing resistor there?
>>
>> What would be the best way to approach looking up one to get, when no
>> other info is oprovided at to type or brand?
>
> Normally one would infer type (such as say wirewound if it has to pass
> a high current ) from the context of the circuit.
>
> All resisors are 'current sensing' so to speak.
>
> Graham
>
>
I'm just learning (on my own) - don't yet know enough to infer much of
anything ;)
- Kris
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Author: qrkDate: 13:20 15-07-08
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On Mon, 14 Jul 2008 18:35:12 -0500, Kris Krieger <me@dowmuff.in>
wrote:
>If a circuit just calls for something like a 1 Ohm resistor, with no other
>info, would it be bad to use a Current Sensing resistor there?
>
>What would be the best way to approach looking up one to get, when no other
>info is oprovided at to type or brand?
>
>TIA!
>
>- Kris
You need to know what sort of current will be passing thru the
resistor. From there, you can determine the power rating of the
resistor. It's overkill (size, cost) to use a 100W resistor if you
only need a 0.1W rated unit.
--
Mark
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Author: Kris KriegerDate: 13:24 15-07-08
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Rich Grise <rich@example.net> wrote in
news:pan.2008.07.15.17.04.07.526497@example.net:
> On Mon, 14 Jul 2008 18:35:12 -0500, Kris Krieger wrote:
>
>> If a circuit just calls for something like a 1 Ohm resistor, with no
>> other info, would it be bad to use a Current Sensing resistor there?
>
> Not at all - that's exactly how it's done.
OH! OK, cool, thanks - I guess the only limiter there is the Ohm value in
the circuit, and the Ohm vlaues available in current-sensing resistors
(they don't seem to go over 10 Ohms).
>>
>> What would be the best way to approach looking up one to get, when no
>> other info is oprovided at to type or brand?
>
> Well, one ohm gives you one volt per amp, so it has to dissipate V * I
> watts - if you're sensing 5 amps, which is 5v across a 1 ohm resistor,
> that's 25 watts!
>
> And, the precision of your measurement will depend on the precision
> of the resistor.
>
> Good Luck!
> Rich
>
Thanks ;) I'm teaching myself, so, although I've been reading a lot of
resources, thre are still some basic questions that they leave out, so I
appreciate teh info :)
- Kris
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Author: Kris KriegerDate: 13:26 15-07-08
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qrk <SpamTrap@spam.net> wrote in
news:dpmp7413llo1hun5t216pes1el38a57i3o@4ax.com:
> On Mon, 14 Jul 2008 18:35:12 -0500, Kris Krieger <me@dowmuff.in>
> wrote:
>
>>If a circuit just calls for something like a 1 Ohm resistor, with no
>>other info, would it be bad to use a Current Sensing resistor there?
>>
>>What would be the best way to approach looking up one to get, when no
>>other info is oprovided at to type or brand?
>>
>>TIA!
>>
>>- Kris
>
> You need to know what sort of current will be passing thru the
> resistor. From there, you can determine the power rating of the
> resistor. It's overkill (size, cost) to use a 100W resistor if you
> only need a 0.1W rated unit.
>
> --
> Mark
>
Yeah, some of these example circuits (my "learning tools") are not clear
when ti coems to certian details - I assume that their typical readers know
a whole lot more than I do ;) and re much more adept than I at figuring
things out, but it'd be nice tohave some of the simpler things noted ;)
Thanks!
- Kris
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Author: Ken S. TuckerDate: 13:51 15-07-08
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On Jul 15, 10:20 am, qrk <SpamT...@spam.net> wrote:
> On Mon, 14 Jul 2008 18:35:12 -0500, Kris Krieger <m...@dowmuff.in>
> wrote:
>
> >If a circuit just calls for something like a 1 Ohm resistor, with no other
> >info, would it be bad to use a Current Sensing resistor there?
>
> >What would be the best way to approach looking up one to get, when no other
> >info is oprovided at to type or brand?
>
> >TIA!
>
> >- Kris
>
> You need to know what sort of current will be passing thru the
> resistor. From there, you can determine the power rating of the
> resistor. It's overkill (size, cost) to use a 100W resistor if you
> only need a 0.1W rated unit.
> Mark
I had the pleasure of servicing an electrically powered
boat out in the boonies of Muskoka.
I needed to measure the current draw from car batteries,
so I cut a bunch of stove wire to short lengths and
crimped them together with good terminals at each
end to make a high watt .1 or .01 resistor, it worked
well.
The problem is to solve for a 100 amp draw without
too much of a voltage drop, so a 0.01 ohm scoffs
1V, and 100W. Anyway, it's fairly easy to make a
short length of Nichrome wire cable, economically.
Ken
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Author: Kris KriegerDate: 16:00 15-07-08
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"Ken S. Tucker" <dynamics@vianet.on.ca> wrote in
news:073c6af6-8ab1-4c79-8f96-935dc8f95e0f@e39g2000hsf.googlegroups.com:
> On Jul 15, 10:20 am, qrk <SpamT...@spam.net> wrote:
>> On Mon, 14 Jul 2008 18:35:12 -0500, Kris Krieger <m...@dowmuff.in>
>> wrote:
>>
>> >If a circuit just calls for something like a 1 Ohm resistor, with no
>> >other info, would it be bad to use a Current Sensing resistor there?
>>
>> >What would be the best way to approach looking up one to get, when
>> >no other info is oprovided at to type or brand?
>>
>> >TIA!
>>
>> >- Kris
>>
>> You need to know what sort of current will be passing thru the
>> resistor. From there, you can determine the power rating of the
>> resistor. It's overkill (size, cost) to use a 100W resistor if you
>> only need a 0.1W rated unit.
>> Mark
>
> I had the pleasure of servicing an electrically powered
> boat out in the boonies of Muskoka.
> I needed to measure the current draw from car batteries,
> so I cut a bunch of stove wire to short lengths and
> crimped them together with good terminals at each
> end to make a high watt .1 or .01 resistor, it worked
> well.
> The problem is to solve for a 100 amp draw without
> too much of a voltage drop, so a 0.01 ohm scoffs
> 1V, and 100W. Anyway, it's fairly easy to make a
> short length of Nichrome wire cable, economically.
> Ken
>
REminds me of that old TV show, "McGiver" <?sp?>, where the guy would
end
up in various sitations and have to come up with all sorts of inventive
devices, using only his wits and maybe a Swiss Army knife ;) Personally, I
could do without the plot, and just go with the "if you're in this
situation, here are some ways to get out" part ;)
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Author: Tim WilliamsDate: 23:11 15-07-08
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Author: Kris KriegerDate: 15:59 16-07-08
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"Tim Williams" <tmoranwms@charter.net> wrote in news:XKdfk.59$m92.1
@newsfe02.lga:
> "Kris Krieger" <me@dowmuff.in> wrote in message
> news:77CdnQxE4vNwnODVnZ2dnUVZ_uudnZ2d@earthlink.com...
>> REminds me of that old TV show, "McGiver" <?sp?>
>
> MacGuyver.
>
>> Personally, I
>> could do without the plot, and just go with the "if you're in this
>> situation, here are some ways to get out" part ;)
>
> You might try Survivorman or Man vs. Nature, on Discovery.
>
> Tim
>
Yeah, I watch those, esp. the latter (IIRC that's the one with Bear Grylls
<?sp?>).
Although I'd admittedly woeful with things electronic (which is why I have
so many simplistic questions re: my over-complex attempted projuect <g!>),
I'm interested in things mechanical, esp. ancient engineering, since it's
at the root fo modern engineering and presents a sort of "back to basics",
or perhaps more accurately "back it inventive thinking" apporach.
Sometimes "how it's made" is interesting, although it tends to skip over a
lot. "How To" shows and websites tend to be things I enjoy ;)
It' snto just the mechanics, tho', it's also fascinating to me because I'm
interested in how the brain works, the process of how people come up with
ideas. Or for that matter, animals, such as teh Green Herons in Florida
who learned to use bait to amke it easier to catch fish.
Thre are too many fascinating things in the universe - I need a lot more
time and a much bigger brain <LOL!>
- Kris
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