Genius behind resistors stripe code and electrolytic cap wire length? [rant]

retrolefty:
Wait to you get as old as me and you can't even read the writing without tons of extra lighting and a big magnifying glass. As an aside I always take a resistance measurement on any resistor I use before soldering it into a circuit, trust me It's worth the extra time expended. :wink:

I'm with Lefty on this one. I can't read the damn things any more without my magnifying glass in my hand. Even chips with their part numbers in dark gray on a slightly darker gray background are a pain.

Even chips with their part numbers in dark gray on a slightly darker gray background are a pain.

I have a magnifier-app on my phone that can negative the colours which has been quite helpful several times for difficult to read text.
It would be superb If I could remap the colour thresholds with it, like when you make a B&W scan, Think I'll mail the developer...:slight_smile:

i think the lead lengths on the electrolytics might be for pick and place machines ?

But they still have to mark the polarity, ( for instance the assemblers I use, preform all the components and cut to length before hand assembly )

The real hassle now is that I have found some wonderful bright LEDs, the long leg is + anode, but so is the flat on the rim, and so is the larger part of the die, both of which are normally - cathode.

When I queried this with my supplier i China, she said they call them the reverse polarity type !

As for chip numbers, the good old days had the numbers printed white, but I think they laser print them now, and often if I cant read it I take a shot with the digital camera, and blow it up on the viewfinder !

I never have to think of the colour code on resistors after 55 years I know them by looking, until my main supplier decided to just sell 2% tolerance or whatever, so now they have the extra stripe, so I am with you Lefty, and always check with my meter.

i think the lead lengths on the electrolytics might be for pick and place machines ?

not the ones we use, caps come on a paper tape and the leads are cut pretty close to that so the machine can use it, and AFAIK the leads are the same length on the tape

PeekabuPi:
You get one mixed pile of resistors and you are gonna waste your time looking for the one you want especially if you have to de-code the stripes or individually measure the reading.

This might be part of your problem. Why are all your resistors in a pile, instead of organized by value?

not the ones we use, caps come on a paper tape and the leads are cut pretty close to that so the machine can use it, and AFAIK the leads are the same length on the tape

Thats true, I was thinking about the big electrolytics, but for the life of me I can't remember if they had different length leads in the old days - but then again a lot of them were axial then, before PCBs.

To save space ,for my R&D bench components, I have resistors, caps and zeners in the same 64 drawers , as some examples

less than 1 ohm and 1 nF in the first drawer,
3R3 with 3n3
100R with 100nF
1K with 1 mF
4.7K with 4.7mF and 4.7 volt zeners ( and 5v regulators )
1M with 1000 mF

It saves trying to read them, but I still measure the resistors anyway....

Its also only 64 drawers to check for restocking

I'm hopeless with colour, always have been and therefore I've always measured unless it's really obvious.

Fortunately almost all my electronics is uC related and as such I only need two resistor values, 10k for pullups and 1k for LEDs. That really helps :slight_smile:


Rob

Yeah, I bought a strip of 500 of each, and each time I need a new one I just get it off the strip. $10 each (strip). And that was for 1% ones. I'm not going to waste an hour to save 5 cents.

Back in 1965 my Dad gave me a big bag of resistors and a small card with the colour code on them.
I set to it putting them into piles of values. By the time I finished I knew the colour codes and threw away the card. I have never forgotten them despite going for months at a time now not reading them as most of my work uses surface mount.
As others say you don't translate the colours one by one, you just look at it an you know it's value.

It was alright when they had a gold or silver stripe, but these new ones I look at and can't work out which end I'm supposed to read from.

But I agree, in the olden days, you would look at the last colour and see the general range (eg. K, ohms, Meg) and then quickly see the other, eg. red/red would be 22.

I teach color codes for myself when I was 8-9 years old, and they will never go away from my head, I probably forget my name before those codes. But, that must have something to do with age, I started to play guitar four years ago, and still haven't learn to read musical notes...

What I think about crying because of color codes... they are so much easier, and you have all the time in the world to read them; try to play music note by note, you will be kicked out the band... I hate notes!!!!
:wink:

Cheers,
Kari

Back in the early 60s I lived near EMI factory, and instead of sorting out their boxes of resistors, they dumped the lot, and we budding radio hams would recycle them from the tip , and seperate them into values, so we got to know the colours well.

( never quite got rid of the tip smell though :slight_smile: )

My favourite colour was always the 47k ( I have to think here to write it down - Yellow Mauve Orange ) which without prompting was also my Daughters favourite " pretty " one whan she used to help me assemble many years ago.

I can read the resistor color codes just fine... EXCEPT when they decide they're going to use all pastel shades for the codes and put them on 1/8th watt resistors... Hmmm, is that lavender or gray? I mean if you're going to use a color code, make the colors easily distinguishable, especially if the part is really small. Of course at my age the extra light and magnification thing is a must as well.

What I will never understand is that most devices are designed by males, and a high percentage of males are colour blind to some degree.

And given that red/green is the most common form of colour blindness, what the hell is with all the devices that use dual colour r/g LEDs, like battery chargers? Often I can't tell the difference, if there are some red and some green I can see that they are different to each other and deduce which is which because some are "redder" than the others. But if they are all the same I've nothing to compare with and I have a hell of a time.

What's wrong with flashing to differentiate? Everyone can tell the difference between a flashing LED and a non-flashing LED.


Rob

2 reasons for the resistor:

  1. it is easier to produce a stripe coding printer than a text printer.
  2. It doesn't matter how the resistor is soldered, the rings are always visible. (also from a distance)

Thinking about this , many of us older guys can't read the codes from a distance on the smaller resistors ( or sometimes up close without a magnifying glass :slight_smile: )

And if I want a leaflet/business card printed, its cheapest with one colour, and goes up for more colours.

If manufacturers used white on a darker background ( as they do on smd caps and res ) you would think it would be cheaper.

They have pad printers that can print on curved surfaces, and have been printing a band plus text on diodes for 50 years now.

I am guessing the diodes are rolled over the ink transfer medium ????

well they make resistors with number codes on them (not only SMD)

ie

but again with axial leads its never going to be in the right place to read and IMO they are just as hard to read as stripes, maybe even harder cause everyone has a different marking ... one company's datasheet uses their in house part number ... figure that out without a freaking spreadsheet.

Boffin1:
They have pad printers that can print on curved surfaces, and have been printing a band plus text on diodes for 50 years now.

I am guessing the diodes are rolled over the ink transfer medium ????

I simply hate those small diodes with unredable text, many times looks like that text is designed to fade away before user get it...

Cheers,
Kari

especially on the glass body models with the black ink

I needed a magnifying glass to read them even in my twenties :slight_smile: