Size of standard resistor?

[BrownTown]

I have looked everywhere on the internets and cannot find the answer to this very simple question. So exactly what is it, how many watts does a standard resistor dissipate? I'm thinking 0.25 but can't be sure. Ordering parts for senior project and need tons of those standard resistors and a couple of larger ones, anywasys, thanks for the time I'm sure tons of people here know the answer off the top of their being as everyone here is an EE.

 

[Colt45]

define standard

generally available from 1/16 or 1/32w up to 300w, and of course bigger..

1/4w usually, 1/2w sometimes...

 

[BrownTown]

Just those normal silly little brown resistors than everyone uses in labs and stuff.

 

[jagec]

I think 1/4W is indeed about the most common, but you can get all kinds for about the same price...check mouser.com.

 

[BrownTown]

I'm on digikey.com buying ~100 parts for my custom PCB, funny thing is with the resistors I am gonna have to purposefully buy the 1% instead of 5% because you can't get 5% in packages less than 5000! .

EDIT: its really funny how all these tiny little things add up though, buying 100 things between .1$ and 10$ and you start getting up there in price, a few 30 cent capacitors here, a 1.5$ heatsink there, and then the ICs and all its gonna be 150$ a board by the time I'm done . Of course last years group used a 1000$ FPGA board so I am still saving some good money going the custom PCB route instead of adapting a prototyping board.

 

[eplebnista]

Don't forget eBay. Sometimes some sellers will have a huge grab bag of new old stock resistors with various sizes/types for cheap.

 

[So]

1/4 Watt is the "typical" lab size in my experience, but 1/2 Watt is also quite common.

 

[esun]

For the typical brown resistor I'd bet 1/4W.

 

[Colt45]

You can get 5% in singles on digikey...
The price breaks aren't very good until you get >200 of each, though.


I seem to remember 1/2w 5% being a few cents cheaper than 1/4w 5%, yageo or whatever.. go figure.


yeah.. double checked.

<value>QBK-ND is 1/4w 5%, min order 5 pieces. eg. 100KQBK-ND for 100k
<value>H-ND is 1/2w 5%, min order 5 pieces. eg. 100KH-ND

1/4w... 5 = $0.27, 200 = $3.82
1/2w... 5 = $0.26, 200 = $3.76

 

[Born2bwire]

If you want to know what the sizes are, check the datasheets. Surface mount packages have standard sizes too.

 

[burr4392]

Try mouser.com I have found their prices to be just as good and you can get good metal film resistors in 1/4watt sizes, cheap and in custom quantities.

 

[Jeff7]

1/4W 5% resistors in packs of 100

 

[PottedMeat]

Hmm doesnt the CAD program give you multiple sizes in the descriptions for components/brands?

 

[BrownTown]

You mean the PCB layout program? In that case yes, I can easily change the sizes of resistors I am using or just add custom sizes, but the point is that the original prototype used the resistors in question and it works, so I'd just as soon not change anything and such. I'm sure all the people who are into motherboards and stuff would want be replacing all the electrolytic capacitors with solid caps and stuff like that, but so far as I am concerned if it ain't broke don't fix it, so I am fixing the part that doesn't work and keeping everything that does.

Well anyways, I already got all the resistor sizes and stuff setup now although I do appreciate everyone providing links of where to buy them cheaper and stuff. Maybe if I were hugely concerned I would go and buy them somewhere else, but since resistors are dirt cheap anyways I am only wasting like 5$ by not getting the best deals so its really not worth shopping around. All the resistors combined barely cost as much as the biggest power supply capacitor and the transformer cost twice as much as all the resistors combined.

 

[Demon-Xanth]

1/4w for leaded, 1/8 or 1/10 for surface mount