What's with the odd numbering on capacitors these days?

That is not the reason either.

It is an engineering thing.

Where is the transition to EIA? That has been in place for decades.

Sheesh.

This is all basic engineering and you two are dopes for not knowing, yet claiming to have been paying attention.

If you cannot see how these decades work into the math, you should choose a different career path.

Finally, little Suezie wakes up.

Despite this being what most of us went by for decades, they ceased operations early this year.

Looks like RoHS is responsible for another death.

So who do we cow down to now? Depends on what you are manufacturing.

Sheesh indeed.

ve

It may be wrong, but saving money is behind a whole lot of engineering decisions, and introducing the E system did save money.

NT

How do new labels on existing products in production save any money?

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Standardisation, consistency. Suppliers only need produce products with one set of values, and they'll suit all end uses (value-wise).

Also inconsistent value spacing (in %age terms) in old pre-E parts meant overlap, with more parts needed to cover each decade to get a given tolerance. The E system is just more business efficient.

NT

Sigh. They didn't change the damn parts, just the way they were labeled.

It was about handling least significant digits in calculations.

Refer to

This is very likely hand in hand with the way we value components.

The decisions also play into ease of design practice.

"Got change for an 18?" "Sure, whaddya want, three sixes or two nines?"

Cheers! Rich

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Changing the nominal value also means changing the tolerance. Its not hard to see you need stock less items to cover a decade with 5% E parts than 5% non-E parts, thats why it was done. Sigh, as you'd say.

NT

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Are you campaigning to be dimbulb's replacement? Obviously, you never used any of the parts labeled under those two systems. There were no 5% electrolytics, no matter what numbering system was used. They were speced as -20/+100% and generally tested around +10% when new. Even now, a 27 µF 160 VDC Sprague electrolytic is rated at -10%/+50% more than 50 years after the standardization of numbering. If you wanted

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Please switch logic on.

This is somewhat immaterial. There were 10% resistors, and with those you need less nominal values to cover a decade under the E system. If you cant see that, try drawing on paper the real value spread of components on a graph, and you'll quickly see that the E series gives no gaps and no overlaps. Pre-E numbering did give overlaps, resulting in more values needing to be stocked per decade, resulting in more business costs. This is very simple stuff.

NT

Not as simple as your small mind. The first resistors were +/- 50%. Early electronics was low tolerance, and the fact that you claim "This is somewhat immaterial" shows your ignorance. Manufacturing processes improved, but they still can't mass produce precision electrolytics for an acceptable price. That was why the specs were -20/+100%. Keep trying to convince yourself that you're right. You do the math. There are still small overlaps, because the E12 numbers were adjusted for whole values, rather than 5 or ten digit numbers. I have over 40 years in electronics, starting in repair. I've worked as a broadcast engineer, and in engineering on a telemetry receiver that sold for $80,000 each. Another model is in orbit. To make the claims you do shows that you are either very ignorant of the facts, or just stupid.

--- Nonsense.

Here's a table of nominal, maximum, and minimum resistance values for the E24 series:

NOMINAL +5% -5%

---------+------+------- 10 10.5 9.5 11 11.55 10.45 12 12.6 11.4 13 13.65 12.35 15 15.75 14.25 16 16.8 15.2 18 18.9 17.1 20 21 19 22 23.1 20.9 24 25.2 22.8 27 28.35 25.65 30 31.5 28.5 33 34.65 31.35 36 37.8 34.2 39 40.95 37.95 43 45.15 40.85 47 49.35 44.65 51 53.55 48.45 56 58.8 53.2 62 65.1 58.9 68 71.4 64.6 75 78.75 71.25 82 86.1 77.9 91 95.55 86.45

Examine it and you'll find that for every nominal value there's either a gap or an overlap from its high side to the low side of the next higher nominal value.

-- JF

Does this mean that they test every unit and group them into tolerances based on their actual value? IOW, if I buy a 10% resistor (can you even get them any more?) is it guaranteed to be off from nominal by at least

Thanks, Rich

yes, but the E series of values ensures these gaps and overlaps are minimised. Cover the same range with a given tolerance and non-E values and theyre no longer minimised, thus more values are needed to cover a decade. The raison d'etre of the E system is very simple.

NT