Why don't resistor vendors list the length of the resistors they sell?

Thread Starter

Lumenosity

Joined Mar 1, 2017
634
RESOLVED (I confused SMD sizes with Axial sizes)

And how do you buy 3.2mm length resistors in bulk quantity in an assortment of ohs ?

I need 3.2mm body length resistors.
1206, 1210, 1812, 3216, 3225 and 3246 all denotes 3.2mm length resistors in varying wattages.

However, I seldom see vendors listing the length of the resistors they have for sale...only the watts rating.
I don't understand this?

Isn't the length of resistors you are buying also important?
In the application I need 3.2mm resistors for, larger resistors are too long.

Thanks
 
Last edited:

Thread Starter

Lumenosity

Joined Mar 1, 2017
634
Ok, I see what I did there.

I confused some 1/4 watt resistors with 1/8th watt...and SMD size charts with through hole sizes

thanks
 
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dl324

Joined Mar 30, 2015
13,282
Beware of a category of through hole resistors called something like "miniature". They're twice the power rating most of us are familiar with.

This is for Yaego resistors:

1632785267117.png
The traditional 1/4W resistor (MFR-25) dimensions can be a 1/2W (MFR50S). That seems like a bad idea to me...
 

crutschow

Joined Mar 14, 2008
27,902
The traditional 1/4W resistor (MFR-25) dimensions can be a 1/2W (MFR50S). That seems like a bad idea to me...
Yes, I agree.
I would expect those 1/4W size resistors to get really hot if dissipating 1/2W, with likely a reduced lifetime and a change in resistance value.
There's little you can do to make a 1/4W sized resistor dissipate 1/2W other then letting it run a lot hotter (perhaps enough to scorch the PCB it's mounted on).
 

cmartinez

Joined Jan 17, 2007
7,455
There's little you can do to make a 1/4W sized resistor dissipate 1/2W other then letting it run a lot hotter (perhaps enough to scorch the PCB it's mounted on).
You can always add a dedicated 5W, 12" dia ventilator running at > 3,000 blowing air directly at it ... :rolleyes:

:p
 
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