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SMD Resistor ?

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  • Member since
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  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
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SMD Resistor ?
Posted by BATMAN on Monday, February 25, 2019 6:57 PM

On regular resistors, they give Watts + Ohm value. On surface mount resistors (SMD) they only provide the Ohm values. What am I missing here? How can I order the right SMD if they don't list the Watts?

I know there must be a simple answer for my simple mind.Laugh

As always, thanks.  

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by BigDaddy on Monday, February 25, 2019 7:14 PM

The ones I see on Ebay have wattage, commonly 1/16 for 0402 1/10 for 0603 and 1/4 w for 1206. 

I assume these are meant for SMD leds.  How does one choose?  They are also on ribbons like the caps I used in my Roy Rogers 6 gun, how do you solder wires to that little thing?

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by RR_Mel on Monday, February 25, 2019 7:18 PM

Here you go Brent
 
 

Size

Length (mm)

Width (mm)

Height (mm)

Watts

0201

0.60

0.30

0.25

0.05

0402

1.00

0.50

0.35

0.031/0.063

0603

1.60

0.80

0.50

0.063

0805

2.00

1.25

0.50

0.100

1206

3.20

1.60

0.60

0.125

1210

3.20

2.60

0.50

0.250

1217

3.00

4.20

0.900

0.250

2010

5.00

2.60

0.70

0.250

2020

5.08

5.08

0.90

0.500

2045

5.00

11.50

0.90

1.000

2512

6.30

3.10

0.60

0.500
 
 
 
 
Mel
 
 
My Model Railroad   
 
Bakersfield, California
 
I'm beginning to realize that aging is not for wimps.
 
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Posted by BATMAN on Monday, February 25, 2019 7:21 PM

BigDaddy
How does one choose? 

http://led.linear1.org/led.wiz 

Thanks, Henry, there is an electronics store in Vancouver that sells SMD resistors, however, their website doesn't list the watts of the SMD resistors, only the Ohms. I found that a little frustrating.

https://leeselectronic.com/en/ 

I guess the 1206 is what I want.

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by BATMAN on Monday, February 25, 2019 7:25 PM

Thanks, Mel, your chart shows .125 W for the 1206. Looks like the 1210 or 1217 as I need a 1/4W.

My eyes are glazing over once again.Laugh

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by richg1998 on Monday, February 25, 2019 7:34 PM

Sometime ago I looked them up in the Digi-Key and Mouser catalogs. It was quite clear.

Rich

If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.

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Posted by tstage on Monday, February 25, 2019 8:41 PM

BigDaddy

The ones I see on Ebay have wattage, commonly 1/16 for 0402 1/10 for 0603 and 1/4 w for 1206. 

I assume these are meant for SMD leds.  How does one choose?  They are also on ribbons like the caps I used in my Roy Rogers 6 gun, how do you solder wires to that little thing?

They even make them as small as 0201s.  Although you can use them in place of regular resistors, SMD resistors are meant mainly for printed circuit boards (PCBs) to span between two soldering pads.  As far as soldering, you tin the ends of an SMD resistor just like you would a resistor wire.

When I was working as a electronics tech a few years back doing prototype work, I was regularly hand-soldering 0603s & 0402s caps & resistors to prototype PCBs and/or wires.  I had an advantage though: Regular access to a high-quality Olympus stereo microscope.  My biggest challenge was hand-soldering a 0201 resistor to a circuit board.  (I actually had to stand the resistor up longways to bridge the solder between the pad and the resistor.)  At nearly 0.02 x 0.01" in size, I'm glad I didn't have to do that very often.

Tom

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Posted by gmpullman on Monday, February 25, 2019 8:56 PM

Of course, you really don't have to use an SMD resistor with a SMD LED. Sure, if space is an issue they're great. All of my SMD LED installs in structures or rolling stock are supplied by 1/8 or 1/4 watt metal film resistors.

In a few passenger cars with many LEDs I had to use half-watt resistors. Anything less got too hot.

Good Luck, Ed

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Posted by BATMAN on Monday, February 25, 2019 9:19 PM

I thought the SMD resistors could be mounted and appear as little boxes on the wall of the RH.Cowboy

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by gmpullman on Monday, February 25, 2019 9:30 PM

BATMAN

I thought the SMD resistors could be mounted and appear as little boxes on the wall of the RH.Cowboy

 

Wow! You sure have more patience than I do... I scattered some details and piping around the walls, including heating pipes but to try to make the wiring as part of the actual details will certainly be a challenging, but rewarding, venture Cool

My resistors and wiring just got tucked up amongst the rafters and beams.

You're having too much FUN!

Cheers, Ed

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