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### Topic: Quick Question About Resistors (Read 859 times)previous topic - next topic ##### Jan 24, 2018, 03:24 am
Does any resistor have lifespan? or theres a years that the resistor itself will destroyed due of to much current that flow into the resistor, I know this is out of topic about arduino but I can't fine any answer about this for my project.

#### groundFungus #1
##### Jan 24, 2018, 03:51 amLast Edit: Jan 24, 2018, 03:52 am by groundFungus
If used within its specifications, a resistor should last many years (virtually forever).  Too much current flow implies use outside the specification, so all bets are off.

#### flounder #2
##### Feb 05, 2018, 01:41 pm
All resistors have two critical specifications: their resistance, and their power rating.  Exceed the power rating, and the lifetime might decrease to single digit years, or double-digit milliseconds.  A good policy is to figure out the wattage you need, and double it.  This is why we can get away with 1/8W resistors in most circuits: I = E/R.  Knowing that W=IE, then the current through a 10K resistor at 5V is 5/10,000 of an amp, or 0.0005A.  W=IE says that the power drawn is 0.0025W, which is a lot smaller than the .125W rating of a 1/8W resistor.  SMT resistors come with smaller ratings, but note that at 10K, a 0.01W resistor would be more than adequate handle the load.

E = IR: It's more than a good idea.  It's the law.

BTW, if I = E/R and W = IE, then W = E^2/R, or 25/10000W = 0.0025W
joe

#### JeromBaines #3
##### Feb 18, 2018, 09:41 pm
All resistors have two critical specifications: their resistance, and their power rating.  Exceed the power rating, and the lifetime might decrease to single digit years, or double-digit milliseconds.  A good policy is to figure out the wattage you need, and double it.  This is why we can get away with 1/8W resistors in most circuits: I = E/R.  Knowing that W=IE, then the current through a 10K resistor at 5V is 5/10,000 of an amp, or 0.0005A.  W=IE says that the power drawn is 0.0025W, which is a lot smaller than the .125W rating of a 1/8W resistor.  SMT resistors come with smaller ratings, but note that at 10K, a 0.01W resistor would be more than adequate handle the load.

E = IR: It's more than a good idea.  It's the law.

BTW, if I = E/R and W = IE, then W = E^2/R, or 25/10000W = 0.0025W
joe
Thanks for the detailed reply!

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