Hi,

I have a set of resistors (see image) where one 1kΩ has dropped to less than 10Ω and darn near ruined a microcontroller.

The package says it can withstand 250V although I'm almost certain peak voltage has not exceeded 50V in any of my experiments where the nominal input is 5V.

Search results say this is an uncommon experience and I purchased the set from a reputable supplier in my area. Bad luck? I'm debating throwing the whole set out in favour of expensive resistors as I am slowly investing into high quality parts. Luck would have it that current was limited elsewhere in my circuit so today's microcontroller was sparred. I'm not so certain about next time..

Regards,
Mark

 

Showing a picture of the actual resistor would have helped. How do we know you simply read the color codes wrong instead of a value changing?
Sometimes the color bands are poor quality, and some colors look like others.

 

Recently, I accidentally destroyed some resistors to the point that they were spewing out flames, smoke and combustion debris.
Surprisingly, they still measured their correct nominal resistance value afterwards.

 

Another thing, as I my eyes age showing preliminary indications of cataracts, it is becoming more difficult for me to discern between certain colours, brown, red, and orange, for example, besides the fact that some resistors are badly coloured in the first place.

 

Mystery solved. Turns out I mistook a 12Ω for 1kΩ with the red and black bands reversed. I don't recall taking one out of the set, evidently there are still 9 left on the tape. Unfortunately the distinction between gold and brown is poor at best and yellows don't show up at all unless well lit.

This topic can be placed in the dumb-dumb category haha

 

Live and learn, I test every single resistor before using them.

I have never trusted my eyes...or the color bands.

 

Partial True Color Perception is my issue. I can distinguish the differences between Brown, Red and Green IF I have sufficient light and magnification. When it comes to Blue and Purple I have a real hard time. I have to stop and ask myself if I see any Red in the Blue. If I see Red then it's Purple. I've done that thousands of times with much success. But like some of the other aging people here, I, too, am experiencing more difficulty discerning colors. My electronics hobby is slowing down and I'm moving more towards wood working.

 

Live and learn, I test every single resistor before using them.

I have never trusted my eyes...or the color bands.

Nothing like having a DMM handy.
In a recent long period of furious intense analog designs, saved me to commit mistake after mistake.

 

For one-off projects, I typically measure resistors before use.

 

Another thing, as I my eyes age showing preliminary indications of cataracts, it is becoming more difficult for me to discern between certain colours, brown, red, and orange, for example, besides the fact that some resistors are badly coloured in the first place.

My old vision was immensely improved with cataracts surgery. Now things look very clear and colours are vivid.
Very cheap resistors have red, orange, brown and gold using the same paint colour. Green and blue also use the same colour.

My old hearing was immensely improved with hearing aids that can do tricks that normal hearing can't do.

Hey, I am 76 and I can run fast like a younger guy.

 

Partial True Color Perception is my issue. I can distinguish the differences between Brown, Red and Green IF I have sufficient light and magnification. When it comes to Blue and Purple I have a real hard time. I have to stop and ask myself if I see any Red in the Blue. If I see Red then it's Purple. I've done that thousands of times with much success. But like some of the other aging people here, I, too, am experiencing more difficulty discerning colors. My electronics hobby is slowing down and I'm moving more towards wood working.

As your vision deteriorates, moving towards hobbies involving high speed saw blades is a good idea.

 

My old vision was immensely improved with cataracts surgery. Now things look very clear and colours are vivid.
Very cheap resistors have red, orange, brown and gold using the same paint colour. Green and blue also use the same colour.

My old hearing was immensely improved with hearing aids that can do tricks that normal hearing can't do.

Hey, I am 76 and I can run fast like a younger guy.

Your birth certificate indicates 76 but with all of your replacement parts, your effective age is likely lower.

 

Old things like me (76) usually get improvements (recalls?) done to them. My tonsils and appendix were removed but never replaced.
After a heart attack two of my plugged up heart arteries got stents installed to keep them open, a big improvement that saved my life. 3 shots of Covid-19 vaccine and Flu shots every year are also saving my life. I got hepatitis vaccines when travelling.

 

Another thing, as I my eyes age showing preliminary indications of cataracts, it is becoming more difficult for me to discern between certain colours, brown, red, and orange, for example, besides the fact that some resistors are badly coloured in the first place.

That and some cheap LED lamps have enough UV in the light to cause some bands to fluoresce to another color entirely.

 

Good to know I'm not the only one who struggles with tiny lines on a piece of plastic. I generally keep my components well sorted and I check resistors often however I use 1k, 10k and 100k most so I just grab what's on top. That being said who knows how many circuits I used the 12Ω in where I meant to use 1kΩ. I was testing two IR LEDs on my camera and noticed one super bright which measured 110mA! Luckily I was using a 3.3V pin so it must have found a balance point because it was continuous for a few minutes and both the LED and uC are fine.

Adventures in electronics

 

I can go one better... A few months ago I was replacing a couple of bulbs with 3mm LEDs in a moving coil meter and forgot to use a resistor at all.. They didn't last very long

 

Turns out I mistook a 12Ω for 1kΩ with the red and black bands reversed.

Welcome to AAC. Likely we've all made similar mistakes. Just means "You're one of us."

 

Both before and after cataract surgery my ability to read the color codes on metal film resistors is greatly enhanced when using a small white LED flashlight with a particular LED in it. I found that the color stripes would undergo metamerism when viewed under various light sources. Now that flashlight and a magnifying glass are always at the ready.

 

As your vision deteriorates, moving towards hobbies involving high speed saw blades is a good idea.

Excellent point. However, I'm acutely aware of spinning cutters and the potential for loose clothing getting snagged and pulled into the blades. But I laugh with you on your comment.

Both before and after cataract surgery my ability to read the color codes on metal film resistors is greatly enhanced when using a small white LED flashlight with a particular LED in it. I found that the color stripes would undergo metamerism when viewed under various light sources. Now that flashlight and a magnifying glass are always at the ready.

I recall arguments here on this forum about colors on a resistor. When I see what appears to me as Red Red Orange on MY screens, others, and not just a few, saw Brown Black Yellow. Of course I'm making up the colors, but the point is that what I see on my screen is often different from what the majority sees on their screens. Hence, if someone posts a picture of a resistor and asks what the color code translates to - I stay the heck away from answering because I have no idea how MY screens may be altering the colors. Nor do I know what sort of lighting the TS may be asking about used.

 

That and some cheap LED lamps have enough UV in the light to cause some bands to fluoresce to another color entirely.

Which begs the age-old question, if it fluoresces in light, what color would it be in the dark?