General > General Technical Chat
why is the US not Metric
<< < (161/291) > >>
vk6zgo:

--- Quote from: vk6zgo on December 08, 2019, 06:59:19 am ---
--- Quote from: bsfeechannel on December 07, 2019, 10:41:07 pm ---
--- Quote from: vk6zgo on December 07, 2019, 08:02:50 am ---
--- Quote from: bsfeechannel on December 07, 2019, 02:44:41 am ---
--- End quote ---
I assume you did notice however, that they use both nF & decimal parts of a uF, as well as decimal parts of a M \$\Omega\$!

--- End quote ---

The filter caps are in µF, the "low frequency" caps are in nF, while the RF-related caps are in pF.

The resistors involved in supplying power are in Ω or kΩ. The resistors that bias the VCL11 tube or convey signal are all in MΩ.

The person who drew this schematic was trying to use the prefixes as a specific unit for a specific application for the same measure, something that the metric system came to abolish. By the way, the nano and the pico prefixes were officially adopted by the SI in 1960. Although you can find them in schematics before that year.

--- End quote ---

"pico" as in "picofarads" was in common use elsewhere than EU, well before 1960, & may have been common for other measurements
which would not normally have come to the notice of those working in everyday Electronics.
It seems that the schematic you found was a "transitional' form.

--- End quote ---

I don't normally quote myself, but there is very useful resource available on line, if someone is curious, as I was, about exactly when "picofarad" came into general use.
This is a collection of the "Wireless Institute of Australia's" journal "Amateur Radio" .
https://www.armag.vk6uu.id.au/index.html
The first reference to "pF" appears in mid 1947.

It then becomes well established in mid 1948, then more & more dominant, having pretty much routed the forces of "uuF' (or "mmf") by mid 1950.

At least as far as the usage for capacitors, SI seems to have been more reactive than proactive!
KL27x:
Even the actual engine-eer of the old steamship or locomotive didn't care anything for a measuring system.

The engine-eer was the guy(s) shoveling coal into the furnace under the boiler. They would have to watch a pressure gauge. They weren't reading off PSI or kilopascals or bars or inches of mercury. They were watching a dial with a red line on it and putting that needle where the conductor/captain has requested in terms of a fraction or percentage. Full steam? All the way to the red line. Half steam? Halfway. 

In our modern cars, we press a gas pedal to regulate the engine torque. The actual engineers have given the pedals the response they have. The length of throw, the linearity of the response, etc. And this basically gets tuned by test driving and tweaking. Plus, there can be some differences in how the controls respond due to nothing more than personal preference. Like how BMW puts 70% of braking force in the first 4mm of pedal travel. The driver is experiencing the results of the engineering, not the measuring system used to do it. The temp gauge, ditto. Do you know what temp your engine runs at in C or F? I only care that the needle in the middle of the temp gauge and the light is off. I've never had a car that displays gallons or liters of gas. There's just a needle and a mark every quarter.


--- Quote ---Responses like "we'll never metricate our road signs because we don't care" serve the US no purpose and make the country look like a land of morons.
--- End quote ---
Apologies to other Americans. My personal view is that most Americas don't care about metricating, ever. In fact the majority would be against change. The same way that Swedes didn't want to switch to driving on the right. Like bsfeechannel has said, this is one of those things that wouldn't happen unless the government circumvented the popular vote. But in this case, we really don't have a befit from doing this other than politics and money changing hands. So I think the majority of Americans are perfectly justified.

This isn't to say that some university (idealistic, book-learned) led movement might not ever get a voting majority. In today's internet age, you never know what movement will get temporarily united people with nothing better to do than to experience the rush of exerting their collective power to do moronic things. (Which this is a staple thing to do in any change of power; change for the sake of change).

I would guess that even the majority of Americans who have immigrated as an adult from a pure metric country would be against change after 3 months of living here. It just doesn't matter, once you have gotten used to it. In our grocery stores, the price of everything is marked in on the shelf in dollars/oz for comparing prices between products sold in different sized containers, even.   

Do you think the electronics component industry would benefit by changing all 2.54mm spaced components and breadboards to 2.50mm spacing? Or would this just cause us all extra work and expense?

Most of our engineers use metric. Our architects and civil engineers use a lot of imperial, still. And they are totally fine with manipulating the physical world in metric and/or imperial. Most EE have to deal with tons of arbitrary choices and decisions. They have a million ways to achieve the end results. Dealing with optimizing input and output ranges at every stage. Metric and imperial is nothing. Not but a drop in an ocean. Not but a state of mind.

If you think this "makes the country look like a land of morons," that would be your opinion, bsfeechannel. W/e country you hail from thanks you for not wearing its flag. 

This "land of morons" maintains its economy and standard of living by maintaining a technology gap/advantage. This is why we spend so much on military and for subsidizing our airplane and other tech industries. 60 years ago it was the auto industry, but the world has caught up, there.

One of the things I personally like about imperial: if you can engineer in imperial, you can (and you probably have to) engineer in any other system, including metric. If you can engineer in metric, you could be a productive-enough cog in a larger machine via monkey-see monkey-do... but you might still be a moron who confuses the real world for numbers. The relationships are real. The formula which describe those relationships are real. The numbers of the units are a figment of your imagination.

Take the ATC example. You could say that km/hr is better than knots, because altitude is in meters. But "per hour" is completely arbitrary, too. Yes, there is a relationship between speed and distance, but the ratios are arbitrary. In engineering, you are constantly adjusting a knob so the signal of interest fits on the screen. The numbers never go exactly to 10 until an engineer determines what the range is and puts the knob on there that goes to 10.
rstofer:

--- Quote from: Tepe on December 06, 2019, 11:56:32 am ---
It's not the cost that keeps the US from metricating the road signs, it is lack of will and that is totally understandable. It wouldn't really serve any purpose.

--- End quote ---

Why are we still nibbling around this topic.  Look, it's really as simple as this:  The US is not going to have some low rent country (or association of countries) tell us how to measure stuff.  See?  Simple!  Work from that premise and see where it takes you.  Pretty much where we are today.  Once people are told the metric standards are held in France, a member of the EU, it's game over in terms of conversion.  There's no way in the world we are giving up our sovereignty to the EU.  We can see how it's working out for the UK.

Those who are compelled for other reasons to use metric will use it.  Science, for example, is slightly easier using metric units but there are equivalent conventional units that work just as well.  But not engineering.  Structural is still in KIPS, HVAC is still in CFM, FPM or GPM, Civil is still in feet and inches and Mechanical (omitting HVAC) is still primarily conventional units.  Electrical (as in power, industrial, etc) is still conventional units including AWG and MCM.  In other words, all traditional Professional Engineering is still in conventional units.  Other kinds of engineering (eg biomedical) is not in the family of Professional Engineering and is likely metric in any event.  But you certainly can't say US engineering is metric.  It isn't.  And it won't be!  Ever!

How is it that those who want us to change are from countries of minimal accomplishments?  They want to drag us down to their level, that's why!  The EU tries to level the playing field such that high rent countries don't outperform the others.  They don't want competition, they want 'equaity'.

It's like that NHS thing.  The standard of care in the UK is to get an appointment in 12 weeks.  In 12 weeks I could be dead!  I can get an appointment with my HMO for the same day if the triage suggests things are serious.  I can go to one  facility for everything except overnight stays.  MRI, ECG, Lab, GP, Specialists are all in the same facility.  For the more serious stuff, I can go to any hospital emergency room and the cost is covered by my HMO.  Sure, it costs more than a buck ninety eight per month but it's worth it.  All socialized medicine accomplishes is to drag everybody down to the same level of misery.  Same as socialized anything else!

It's interesting that Boris Johnson wants to pull the UK back to imperial units.  That ought to be fun to watch!  I can see the smoke pouring out of Juncker's ears when that begins.  Yes, I know he is out of office...

As I said much earlier in this thread, we aren't going to change.  Certain fields already use metric but the people use conventional units and always will.

Anybody keep track of Nobel Prizes by country?  The US doesn't quite keep up with the idea that we have more than all the other countries combined but it's surprisingly close.  Somehow our 'morons' are smarter than everybody else's 'morons', combined.

OK, that's just science.  What about something more important:  Money!  The DOW is up more than 42% since the inauguration.  If you have a boatload of money in your retirement account, 42% of a boatload is still a boatload of money.  Lowest unemployment in 50 years.  Lowest unemployment of minorities, ever!  Modest wage growth but it's starting to tick up, labor is tight.  How are the European countries doing?  Last I heard, not too well!  And the reason unemployment was so low in the '60s (the 50 years ago thing) was the vast number of people drug into the military.

I expect the US to stand pat.  We're holding all the high cards and don't really need to concern ourselves with the other players.

rstofer:

--- Quote from: KL27x on December 08, 2019, 01:59:25 pm ---
Take the ATC example. You could say that km/hr is better than knots, because altitude is in meters. But "per hour" is completely arbitrary, too. Yes, there is a relationship between speed and distance, but the ratios are arbitrary. In engineering, you are constantly adjusting a knob so the signal of interest fits on the screen. The numbers never go exactly to 10 until an engineer determines what the range is and puts the knob on there that goes to 10.

--- End quote ---

Knots are kind of handy since 1 nautical miie is 1 minute of arc in terms of latitude or 1 minute of arc at the equator in terms of longitude.  60 nautical miles => 1 degree of arc similarly defined.

For ATC, radians/unit of time would be terrific because it would account for altitude.

By Chevy truck has a display of Range - gallons in the tank and burn rate over the last <insert some interval of something here>.  It's kind of handy.  I have more than 400 miles of range when I fill up and I seldom let it get below 200 miles.  One of the places I frequent is almost exactly 100 miles round trip.  It's way out in the country, it wouldn't pay to run out of gas.

My Chevy Bolt has a range estimate as well.  It's important to watch this because the battery won't last forever.  In cooler weather, 30% of battery usage is by the heating system leaving only 70% for travel.  That's a really big deal if you only have 200 miles of range, reduced to 140 miles, and your destination is 100 miles round trip.  Sure, it will make it and still have 40 miles remaining when I get home but, again, it's way out in the country and I'm too old to push a car.  The Bolt has a lot of cool instrumentation.  The EEs really had fun with that thing!

There are several ways of specifying altitude, some based on mean sea level, some on barometric pressure (actual and nominal), some based on radar.  They all get a different answer.  It's complicated...

https://en.wikipedia.org/wiki/Altitude
KL27x:
^Yeah, the nautical mile is adjusted for degree of arc. But ground speed is slightly different than plane's vector speed, due to elevation. So it works pretty close to perfect for boats, but there would be a slight error vs the vector speed of a plane, then another error against the airspeed as measured in the horizontal axis of the physical plane vs its true vector. So yeah, the nautical mile is what it is for a good reason, but even then the real world is simply messy. And engineers deal with it, so that the end user can control and utilize the technology.

I pretty much agree with a lot of your sentiment, rstopher, but I think the tone is a bit needlessly harsh and the post a bit unfocused. We were making some progress, here. Don't open the door, again. :)
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod