Comments on: The Lenght Of Resistors

By: Jestine Yong

Jestine Yong — Fri, 09 Nov 2012 12:21:48 +0000

In reply to yosry mostafa.

Hi Yosry,

Even on other type like the metal oxide film resistor the length still the same.

Jestine

Likes(0)Dislikes(0)

By: yosry mostafa

yosry mostafa — Fri, 09 Nov 2012 00:30:10 +0000

i think the relation between the length of resistor and its wattage depend on the type of material which the resistor has made.
so these lengths belonging to one type of resistor

Likes(0)Dislikes(0)

By: Jestine Yong

Jestine Yong — Fri, 17 Aug 2012 16:36:53 +0000

In reply to beh.

Hi Beh,

Yes you are right, the bigger resistor is needed if the consumption power is high.

Jestine

Likes(0)Dislikes(0)

By: beh

beh — Thu, 16 Aug 2012 18:35:04 +0000

HI MR YONG
i think a bigger phisical size resistor must have a bigger consumption of energy and must have a bigger watt(normaly). specially in carbon made resistors
for example 2 watt resistor needs more than 4 cm phisical size .
beh

Likes(0)Dislikes(0)

By: Jestine Yong

Jestine Yong — Wed, 15 Aug 2012 16:43:53 +0000

In reply to Alex.

Hi Alex,

Those resistors were measured within the body "resistor element" and I found that the diameter is more or less the same bewteen resistors in one board as compare to another type of board. If you are in electronics repair, there is one rule of if a ressitor always burn then the replacement should be slightly higher than the original one. if it is a 1/4 watt then you use 1/2 watt.

Jestine

Likes(0)Dislikes(0)

By: Alex

Alex — Wed, 15 Aug 2012 05:12:07 +0000

Hi Jestine,
This may seem like an odd (or silly) question,
but do you mean the length of a resistor straight from a roll of new resistors taken from your parts cabinet (with the leads uncropped) or the length of the actual "resistor element" already on a PCB (where the leads are folded and cropped after insertion and soldering), but it is clear "there are big ones and small ones".
if I am purchasing resistors (more for projects than repair) I tend to get a 0.25W (1/4 W) resistor unless the application requires a bigger one for safety (such as a loudspeaker crossover unit, or a series resistor for a higher current LED - for instance a project I built to automatically send IR codes to audio equipment uses a 100R resistor at 0.5 W rather than a 220R at 0.25W that are normally used with LEDs for this system (with +5V DC supply).
The only reason I pick this power rating is it seems to be cost effective, not too big nor too small (I am not that good yet with really small components!) and it was "what I used as a boy, from hich school age!"
So I tend to instinctively know how big this should be. But other ones I am not always as sure.
in the case of repair, I would think a rough guide to the length of the resistor element on the PCB and also itrs diameter would be helpful, as most technicians would be faced with replacing an unknown resistor on a PCB which has burned (and thus power rating is important, as we would not want it to burn again, or worse cause anything else to overheat!)
Alex

Likes(0)Dislikes(0)