What's the Wattage of a SMD Resistor?

  • Thread starter Watson A.Name - "Watt Sun
  • Start date
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Watson A.Name - "Watt Sun

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I sawed a chunk of PC board off a controller board of a defunct CD-ROM
drive. This was the LED and driver circuit, and it had two '910' or
91 ohm SMD resistors in series with each other and the LED and SMD
transistor. My guess is that this circuit was supplied with 5VDC, so
180 ohms should allow an LED current somewhere in the 12 to 15 mA
range. So what if I go to 6V or so for the supply? What's the max
power dissipation for a resistor that measures about .032" or .8 mm
wide (I can't measure the length because of the solder)?


--
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Don't be ripped off by the big book dealers. Go to the URL
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Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
"Watson A.Name - Watt Sun" wrote:
I sawed a chunk of PC board off a controller board of a defunct CD-ROM
drive. This was the LED and driver circuit, and it had two '910' or
91 ohm SMD resistors in series with each other and the LED and SMD
transistor. My guess is that this circuit was supplied with 5VDC, so
180 ohms should allow an LED current somewhere in the 12 to 15 mA
range. So what if I go to 6V or so for the supply? What's the max
power dissipation for a resistor that measures about .032" or .8 mm
wide (I can't measure the length because of the solder)?

--
Click to expand...
.06 X .03 = 0603, 1/10W,

--


Michael A. Terrell
Central Florida
 
SMD film resistor size Power rating

1.0 x 0.5 mm 63mw
1.6 x 0.8 mm 100 mw
2.0 x 1.25 mm 125mw
3.2 x 1.6 mm 250 mw
3.2 x 2.5 mm 330 mw

Hope this info helps

Cyrus


"Watson A.Name - Watt Sun" <alondra101@hotmail.com> wrote in message
news:MPG.19ed1c4f87b6dc4e98977c@news.dslextreme.com...
I sawed a chunk of PC board off a controller board of a defunct CD-ROM
drive. This was the LED and driver circuit, and it had two '910' or
91 ohm SMD resistors in series with each other and the LED and SMD
transistor. My guess is that this circuit was supplied with 5VDC, so
180 ohms should allow an LED current somewhere in the 12 to 15 mA
range. So what if I go to 6V or so for the supply? What's the max
power dissipation for a resistor that measures about .032" or .8 mm
wide (I can't measure the length because of the solder)?


--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
Click to expand...
 
In article <00Mgb.15973$gi2.8698@fed1read01>, CyrusM@fox.net
mentioned...
SMD film resistor size Power rating

1.0 x 0.5 mm 63mw
1.6 x 0.8 mm 100 mw
2.0 x 1.25 mm 125mw
3.2 x 1.6 mm 250 mw
3.2 x 2.5 mm 330 mw

Hope this info helps

Cyrus
Click to expand...
Yes, it does. Thank you. Now if I can get the calipers on the
resistor...

"Watson A.Name - Watt Sun" <alondra101@hotmail.com> wrote in message
news:MPG.19ed1c4f87b6dc4e98977c@news.dslextreme.com...
I sawed a chunk of PC board off a controller board of a defunct CD-ROM
drive. This was the LED and driver circuit, and it had two '910' or
91 ohm SMD resistors in series with each other and the LED and SMD
transistor. My guess is that this circuit was supplied with 5VDC, so
180 ohms should allow an LED current somewhere in the 12 to 15 mA
range. So what if I go to 6V or so for the supply? What's the max
power dissipation for a resistor that measures about .032" or .8 mm
wide (I can't measure the length because of the solder)?


--
Click to expand...

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
On Wed, 8 Oct 2003 05:41:52 -0700, Watson A.Name - "Watt Sun"
<alondra101@hotmail.com> wrote:

In article <00Mgb.15973$gi2.8698@fed1read01>, CyrusM@fox.net
mentioned...
SMD film resistor size Power rating

1.0 x 0.5 mm 63mw
1.6 x 0.8 mm 100 mw
2.0 x 1.25 mm 125mw
3.2 x 1.6 mm 250 mw
3.2 x 2.5 mm 330 mw

Hope this info helps

Cyrus

Yes, it does. Thank you. Now if I can get the calipers on the
resistor...
Click to expand...
Or snap a digital photo with a scale bar in the frame...

--
Rich Webb Norfolk, VA
 
In article <a939ov4muc6ibr8ht9d19p0g5birc4d28v@4ax.com>,
bbew.ar@mapson.nozirev.ten mentioned...
On Wed, 8 Oct 2003 05:41:52 -0700, Watson A.Name - "Watt Sun"
alondra101@hotmail.com> wrote:

In article <00Mgb.15973$gi2.8698@fed1read01>, CyrusM@fox.net
mentioned...
SMD film resistor size Power rating

1.0 x 0.5 mm 63mw
1.6 x 0.8 mm 100 mw
2.0 x 1.25 mm 125mw
3.2 x 1.6 mm 250 mw
3.2 x 2.5 mm 330 mw

Hope this info helps

Cyrus

Yes, it does. Thank you. Now if I can get the calipers on the
resistor...

Or snap a digital photo with a scale bar in the frame...
Click to expand...
What's the significance of the photo? How about a pencil and paper,
or just type the values read off the scale into the PC?

Wish I had on of those eye loupes with the scale built-in.

--
@@F@r@o@m@@O@r@a@n@g@e@@C@o@u@n@t@y@,@@C@a@l@,@@w@h@e@r@e@@
###Got a Question about ELECTRONICS? Check HERE First:###
http://users.pandora.be/educypedia/electronics/databank.htm
My email address is whitelisted. *All* email sent to it
goes directly to the trash unless you add NOSPAM in the
Subject: line with other stuff. alondra101 <at> hotmail.com
Don't be ripped off by the big book dealers. Go to the URL
that will give you a choice and save you money(up to half).
http://www.everybookstore.com You'll be glad you did!
Just when you thought you had all this figured out, the gov't
changed it: http://physics.nist.gov/cuu/Units/binary.html
@@t@h@e@@a@f@f@l@u@e@n@t@@m@e@e@t@@t@h@e@@E@f@f@l@u@e@n@t@@
 
In article <MPG.19ee80f0a6f47dc198977f@news.dslextreme.com>,
Watson A.Name - "Watt Sun" <alondra101@hotmail.com> wrote:

In article <a939ov4muc6ibr8ht9d19p0g5birc4d28v@4ax.com>,
bbew.ar@mapson.nozirev.ten mentioned...
On Wed, 8 Oct 2003 05:41:52 -0700, Watson A.Name - "Watt Sun"
alondra101@hotmail.com> wrote:

In article <00Mgb.15973$gi2.8698@fed1read01>, CyrusM@fox.net
mentioned...
SMD film resistor size Power rating

1.0 x 0.5 mm 63mw
1.6 x 0.8 mm 100 mw
2.0 x 1.25 mm 125mw
3.2 x 1.6 mm 250 mw
3.2 x 2.5 mm 330 mw

Hope this info helps

Cyrus

Yes, it does. Thank you. Now if I can get the calipers on the
resistor...

Or snap a digital photo with a scale bar in the frame...

What's the significance of the photo? How about a pencil and paper,
or just type the values read off the scale into the PC?

Wish I had on of those eye loupes with the scale built-in.
Click to expand...
You use the enlarged calibrated photo for more accuracy. It's tough to
measure mounted 1 mm objects by hand.

Al

--
There's never enough time to do it right the first time.......
 
Al wrote:

In article <MPG.19ee80f0a6f47dc198977f@news.dslextreme.com>,
Watson A.Name - "Watt Sun" <alondra101@hotmail.com> wrote:


In article <a939ov4muc6ibr8ht9d19p0g5birc4d28v@4ax.com>,
bbew.ar@mapson.nozirev.ten mentioned...

On Wed, 8 Oct 2003 05:41:52 -0700, Watson A.Name - "Watt Sun"
alondra101@hotmail.com> wrote:


In article <00Mgb.15973$gi2.8698@fed1read01>, CyrusM@fox.net
mentioned...

SMD film resistor size Power rating

1.0 x 0.5 mm 63mw
1.6 x 0.8 mm 100 mw
2.0 x 1.25 mm 125mw
3.2 x 1.6 mm 250 mw
3.2 x 2.5 mm 330 mw

Hope this info helps

Cyrus

Yes, it does. Thank you. Now if I can get the calipers on the
resistor...

Or snap a digital photo with a scale bar in the frame...

What's the significance of the photo? How about a pencil and paper,
or just type the values read off the scale into the PC?

Wish I had on of those eye loupes with the scale built-in.


You use the enlarged calibrated photo for more accuracy. It's tough to
measure mounted 1 mm objects by hand.

Al
Click to expand...
I go to Google and type in scale eye loupe and what pops up? A page of
Ebay stuff, which, besides the search item, has a "Will eBay Ban this
Nude Arnold Schwarzenegger" doll! WTF??

Anyway, this is what I had in mind, a magnifier with a scale or
graticule, so one can compare the size of objects with the scale.
http://www.2spi.com/catalog/magnifiers/spi-linen-testers.shtml

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