How to identify if the resistor is out of tolerance?


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Ask it a question related to history based on ethics of today versus ethics of the target time period. If you don't get the current Politically Correct answer, it is out of tolerance. ;)

Seriously, though. The best way is to remove it from the circuit and measure the resistance with a suitably accurate VOM or DMM meter. Place the probes as close as possible to the body of the resistor to rule out lead resistance. Compare your findings with the value range derived from the resistor markings.

In other words, what "they said" already.

Qa

iceng1 year ago

I have seen a glass germanium diode labeled backwards ie the cathode band was on the anode end..

It depends on the tolerance ! A multimeter will test ones that are >1% tolerance, you need a serious test instrument for <1%

True, but if you design with 1% resistors you should be way over the point to ask questions like this.

Good point..

rickharris1 year ago

I might add that in 50 years of working with electronics an out of tolerance resistor is not a fault I have ever seen.

I have, especially if the magic smoke nearly came out

verence1 year ago

By measuring it and check whether the measured value is within set resistance plus/minus tolerance. How else?

That's not how you do it.

You take a sprig of broccoli wave it over the resistor and say the mystical words, "Enny beany chilly beany the spirits are about to speak."

Then the resistor will tell you if it is out of tolerance.

I think you are confusing resistors with transistors here!
The only thing I use to check resistor tolerances is my "Magic Eye" powered by space waves.
For those unfamiliar: The magic eye was used in old tube radios to show the quality of the signal received.
Once the Magic Eye is powered up and glowing green you hold it over the resistor with about 1cm of distance.
Depending on the tolerance of the resistor the full green glow will focus to a small dot.
The lower the tolerance the smaller the green dot.
Far more accurate than your broccoli as you never really know how old it is unless it comes fresh from your garden.
I have seen resistors failing to report the tolerance as they did not like the old broccoli!

Easy solution

ball.jpg
iceng1 year ago

As Verence says use a multimeter ohm scale to measure the disconnected resistor and compare the reading with the value colors imprinted and the tolerance high and low values allowed by the tolerance color band.

Don't know how to read see this

https://www.instructables.com/id/Color-Code-and-Typ...

if the value is low be sure to measure the value of resistance of the shorted leads and subtract that small value from all subsequent readings to get the real resistor value ......