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why is the US not Metric
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vad:

--- Quote from: richard.cs on October 25, 2019, 02:51:02 pm ---You might as well ask when North America will join the 230 V world :-D Lots of advantages there (~3 kW available for common domestic appliances, lower final circuit currents leading to fewer fires and higher energy efficiency, eventual death of split-phase and weird stuff like high leg delta).
--- End quote ---
I would rather see the world adopting low-voltage DC residential electric circuits for lighting and electronics. At home I have about a hundred devices ranging from LED lamps to phone charges that don’t really need 120V, each with its own mains-operated LED driver or isolated SMPS (what a waste!), and only a handful appliances that genuinely benefit from 120VAC and two-phase 240VAC supply.
tooki:

--- Quote from: jonovid on October 25, 2019, 10:24:21 am ---whats the attraction to the use of old imperial measurement in the US?
here in Australia everything is Metric,  like most of the world.
why is the US system of measurement the odd one out?

--- End quote ---
Ugh, this topic AGAIN? Why do people feel such a need to rehash this periodically, invariably coming from a place of arrogance at the "backwards" USA? As it happens, there are sound reasons for not bothering to switch to metric, it isn't laziness or obstinance.

First of all, of course, the premise postulated in the thread title isn't even true: while the US certainly isn't all-metric, it's not metric-free, either. Large soda bottles in USA have been 1/2/3 liters for decades, and practically all science and engineering is done in metric now. Medicines have been dosed in milligrams for ages. Temperatures, liquid volumes, weights and lengths/distances are the main things still done in US units.

But here's the little secret the arrogant USA bashers invariably ignore when discussing this issue: their countries aren't all-metric, either!

Here in Europe, a household hose fitting is highly likely to be defined in inches. (Like the one that connects a shower hose to the faucet.) Tire sizes are that bizarre mix of millimeters, ratio, and inches. Old people sometimes still ask for a pound of meat at the butcher. Diamonds are measured in karats. People discuss their TV sizes in inches. The tripod mounts AG6QR mentioned are in inches. And many more things may be given in metric, but actually defined in inches (like the spacing of pins on through-hole ICs. Yeah, it may say 2.54mm, but it's actually dimensioned as 0.1".)

I don't know Australia well enough to tell you which specific things in Australia still use imperial units, but I can say with total conviction that your claim that "everything is in metric" is untrue. Most, yes. All, no.


--- Quote from: themadhippy on October 25, 2019, 05:18:44 pm ---The Americans cant even get there imperial units correct,why are there pints  smaller?

--- End quote ---
The sizes of old units were not unified. The US and UK versions of imperial measurements diverged a LONG time ago, and had each been in use for a long time by the time their respective sizes were actually officially defined, independently of each other. (And in fact, throughout Europe, countless versions of the old measurements were used. They were NEVER unified.) So it's not Americans getting it "wrong", it's that EVERYONE had their own version of each unit before going metric, very much like how each country in the Eurozone had its own independent currency before switching to the Euro.


--- Quote from: German_EE on October 25, 2019, 06:46:04 pm ---Years ago I remember being told that the reason the USA hadn't converted to metric was the cost of retooling, imagine the cost of replacing all those lathes and milling machines, plus the drill bits and everything else.

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It's a real cost for sure, something nobody would make without their being a clear advantage to doing so. And over the years, as the advantages of using metric became obvious, many (most?) US industries did change to metric. American cars have been metric for decades now, for example. (And that transition remains a PITA for mechanics, who must maintain two sets of tools in order to service both younger and old vehicles. It's not just manufacturing that's affected by change, so is post-sales service, and compatibility. And ANY change involves risk. So there needs to be a serious advantage to make it worth doing.)



--- Quote from: German_EE on October 25, 2019, 06:46:04 pm ---Lots of US companies now have their stuff made in Asia, who are quite comfortable working with either system, and the cost of conversion has now shrunk.

--- End quote ---
And as such, the metrication of the USA has continued unabated.


One of the best, least-biased explanations I've found on the reasons for the US not going fully metric is this one:

Monkeh:

--- Quote from: vad on October 25, 2019, 07:42:56 pm ---
--- Quote from: richard.cs on October 25, 2019, 02:51:02 pm ---You might as well ask when North America will join the 230 V world :-D Lots of advantages there (~3 kW available for common domestic appliances, lower final circuit currents leading to fewer fires and higher energy efficiency, eventual death of split-phase and weird stuff like high leg delta).
--- End quote ---
I would rather see the world adopting low-voltage DC residential electric circuits for lighting and electronics. At home I have about a hundred devices ranging from LED lamps to phone charges that don’t really need 120V, each with its own mains-operated LED driver or isolated SMPS (what a waste!), and only a handful appliances that genuinely benefit from 120VAC and two-phase 240VAC supply.

--- End quote ---

So instead you want the greater expense and complexity of switching and protecting DC circuits and, translating to actual standards, the losses involved in ELV distribution.

Yes, this makes much sense.
floobydust:
Living next to the USA, you memorize conversion factors and don't really care what the units are.
Many industries are exclusively Imperial, such as plumbing and piping, wire gauges, lumber.

I like Fahrenheit because it has almost twice the resolution compared to Celsius. Centimeters are harder to estimate compared to the King's foot or inches.
wraper:

--- Quote from: tooki on October 25, 2019, 07:47:58 pm ---And many more things may be given in metric, but actually defined in inches (like the spacing of pins on through-hole ICs. Yeah, it may say 2.54mm, but it's actually dimensioned as 0.1".)

--- End quote ---
Glory to Soviet Union, they did not bother with that crap and simply used 2.50 mm pin pitch. Thus larger pin count ICs while being clones are not directly interchangeable.
Clone of 7400 http://www.kontest.ru/datasheet/unkn0wn/k155la3.pdf
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