General > General Technical Chat
why is the US not Metric
Simon:
--- Quote from: CatalinaWOW on October 27, 2019, 05:40:05 pm ---These last few posts are typical of metric-imperial arguments. I mean golly. If you are able to do electronics you should be able to handle ratios and their inverses. And use each to their best advantage. It is kind of like arguing whether sines or arcsines are better. Same applies to measurement systems.
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No because L/100km has no practical use other than to say "oh look, this onu uses less than this one". It's not a unit of measure. Sure i can unse it but I want to know how far my car goes on a tank of fuel. Do I now need to measure my fuel tank in units of how many litres it takes to drive 100km? because i could do that but again it's a roundabout measurement. We say km/h not km/5h or h/100km. We cousd and we could work with them but they are not actual units of anything they have to be back converted to something useful.
If i wanted to work out haw many litres I usod per 100km on my last tank I would have to establish L/km or km/L first.
tooki:
--- Quote from: VK3DRB on October 27, 2019, 12:50:26 am ---Besides the Altium grid lines "standard" being a dog's breakfast, many Chinese PCB manufacturers only specify their capability dimensions in imperial measurements (eg: minimum track width 7mils, rather than 0.18mm). This is only to appease US engineers who cannot fathom (sorry, 1.8288m) the metric system |O (Just kidding, sort of!).
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I assure you, it's nothing but smug US haters telling you that Americans can't understand metric. It's been taught in schools for 50+ years now, and American engineers are absolutely, definitely, 100% going to be able to handle millimeters just fine.
--- Quote from: Monkeh on October 27, 2019, 04:27:07 am ---
--- Quote from: james_s on October 27, 2019, 03:31:01 am ---
--- Quote from: Monkeh on October 26, 2019, 10:40:38 pm ---Of course they don't, if they did people would put them in 120V outlets and things would explode. It should be readily apparent that you will require an appropriately non-interchangable fitting for such radically different supplies, whether you go the route of distributing them unreasonable distances or use local regulation..
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Actually they do, well they're 12VDC.
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Well, frankly, that's stupid. :-//
Does not really happen here, with the exception of 110V lamps - but they're fairly restricted in availability.
E: Although it seems there's a handful of them making their way over from China thanks to your influence..
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12V (and even 6V) E27 bulbs are sold in Europe, too, again for campers. I think they're simply one of those items most people are unaware of, because a local grocery, furniture, or lamp store will not sell them. (But you will find them at the camper supply shop.)
It's the restricted availability that keeps people from buying them by mistake. It's not as though 12V (incandescent) E26/E27 bulbs are in any way new. If this were a major problem, it would have reared its head many, many decades ago, when our parents were still in diapers.
--- Quote from: james_s on October 27, 2019, 05:10:19 am ---It's a complete non-issue, I don't think I've ever personally known anyone who put an RV bulb into a household socket. I'm sure someone has done it somewhere but it's certainly not common. They say 12V right on the bulbs, they're significantly more expensive than standard bulbs and while they are fairly widely available you kind of have to go out of your way to get them. If you do give a 12V bulb 120V it just blows out, pop, no drama or excitement. I put a 6V cadelabra base lamp in a 120V socket once when I was a kid, blew it instantly but didn't cause any harm beyond that.
It's not just the US that uses 120V, there are a whole handful of countries:
https://www.school-for-champions.com/science/ac_world_volt_freq_list.htm
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^^^ exactly.
CatalinaWOW:
--- Quote from: Simon on October 27, 2019, 05:47:22 pm ---
--- Quote from: CatalinaWOW on October 27, 2019, 05:40:05 pm ---These last few posts are typical of metric-imperial arguments. I mean golly. If you are able to do electronics you should be able to handle ratios and their inverses. And use each to their best advantage. It is kind of like arguing whether sines or arcsines are better. Same applies to measurement systems.
--- End quote ---
No because L/100km has no practical use other than to say "oh look, this onu uses less than this one". It's not a unit of measure. Sure i can unse it but I want to know how far my car goes on a tank of fuel. Do I now need to measure my fuel tank in units of how many litres it takes to drive 100km? because i could do that but again it's a roundabout measurement. We say km/h not km/5h or h/100km. We cousd and we could work with them but they are not actual units of anything they have to be back converted to something useful.
If i wanted to work out haw many litres I usod per 100km on my last tank I would have to establish L/km or km/L first.
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So Siemens are not a unit of measure? But Ohms are. Or frequency is not a unit of measure but wavelength is? I don't disagree about which is more convenient for your purpose, but surely the people on this forum are bright enough to deal with these things without skipping a beat.
Simon:
they are units of something per 1 of something else. It's metres per second, not metres per 10s. simens is the inverse of ohm, not the inverse of the measurement in ohms times 100
IanB:
--- Quote from: tooki on October 27, 2019, 05:48:42 pm ---12V (and even 6V) E27 bulbs are sold in Europe, too, again for campers. I think they're simply one of those items most people are unaware of, because a local grocery, furniture, or lamp store will not sell them. (But you will find them at the camper supply shop.)
It's the restricted availability that keeps people from buying them by mistake. It's not as though 12V (incandescent) E26/E27 bulbs are in any way new. If this were a major problem, it would have reared its head many, many decades ago, when our parents were still in diapers.
--- End quote ---
I remember being highly amused in 1970's Britain when I discovered a 12 V 60 W bulb with an ES base (for use in a car inspection lamp). At the time all domestic 240 V light fittings used a bayonet cap bulb and so it was impossible to mix things up. There were 240 V bulbs made with an ES or GES base, but these were mainly used in industrial or commercial settings, rarely in homes.
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