Electronic conventions I hate

carbonzit said:

Well, there you go: if you have a good tool that can handle either measurement system, then what's your complaint about non-metric units? Do they really offend you that much?

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Working with imperial/metric components is easy because I don't have to do any measurements myself. I only have to be able to align them nicely.

What I hate about imperial length units (or any other units) is the complexity. There is only one metric unit, the meter, and one unit for area, the square meter.

There are at least 13 length units in the imperial system: thou, inch, foot, yard, chain, furlong, mile, league, fathom, cable, nautical mile, link and rod.
Why two different miles?

And why is acre 1 furlong * 1 chain?

Well, you picked the "weird" units that are only used by certain people in specialized uses. I've never personally met a chain, furlong, league, fathom, cable, nautical mile, link or rod. (Writing about these, I imagine swarthy men standing on the deck of a wooden sailing ship, brandishing various antiquated measuring devices menacingly at each other.)

carbonzit said:

Well, you picked the "weird" units that are only used by certain people in specialized uses. I've never personally met a chain, furlong, league, fathom, cable, nautical mile, link or rod. (Writing about these, I imagine swarthy men standing on the deck of a wooden sailing ship, brandishing various antiquated measuring devices menacingly at each other.)

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That is exactly how I feel about inches, feet, yards, miles and thous... and the rest. (Including this thread. Only the wooden ship now is the internet).

Boncuk said:

the USA would have fallen back exporting cars to overseas countries if the manufacturers hadn't used metric bolts and screws.

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I said the USA has not fallen behind in engineering. Exports was long ago lost to low wage countries.

An Italian Espresso cup has a volume of 10ccm, a Turkish coffee cup has a volume of 20ccm, a German coffee cup has a volume of 100ccm and a

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An american cup of coffee has a volume of 8 ounces. Or 1/2 pint.

Electronic conventions I hate:

Does anyone remember what GHz were called before they were GHz?

Ron

Would it be kilo-megahertz?

BrownOut said:

Would it be kilo-megahertz?

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That sounds right. I'll have to dig into the archives to confirm later.

Yeah, BrownOut got it. Actually it was kilo mega cycles.

Years ago I attended a HP seminar taught by a Stephen Adams of HP. He was an old Hungarian engineer and hated the term Kilo Mega Cycles. Yet, following WWII and Korea there were tons of great electronics surplus including plenty of HF stuff. The dials were labeled Kilo Mega.

Ron

KeepItSimpleStupid said:

We now have a sense of what a liter is because pop./soda comes in these things. In the process of converting, the price went up deceptively.

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Interesting idea about the soda bottles. I do have a very good feel for a liter specifically because of that.

It's easy to remember a yard is very close to a meter and thereby a foot is about a third of a meter. Also, a centimeter is roughly a third of inch. So, you can eyball your inches then they'll be about 3 times that amount in centimeters. One thing I have little trouble with is millimeters from working on cars and bikes with metric fasteners. I have a really good feel for a quantity of 10mm, a very common nut size. Since metric is decimal, that's simply one centimeter.

I have my wrench drawer organized thusly:

Left Side Right Side
8mm 1/4
9mm 5/16
10mm 3/8
11mm 7/16
13mm 1/2
14mm 9/16
15mm 5/8
etc.

Either way I want to think about it, I have the correct wrench at my fingertips

About every so many years someone decides it cute to change things.

When I learned electronics in college frequency was cycles per second. My Senior year they changed Cycles to Hertz. Why didn't they change it to farts per second. OH.....it has to be named after the old fart that invented it. A 2 meter transceiver was 144 cps then it was changed to 144 Hz. Ok that is rear nice now what!

You look at very old electronic drawings capacitors are in MFD. Electric Motors are still MFD. Some where along the way someone changed MFD = uf and pf. Now someone decided we need nf too, well it does save typing space.

I found some electronic drawings online not long ago all the parts were rectangle boxes, there were NO electronic symbols at all. Each rectangle box had the information written inside the box. 5K ohms, .01 uf, etc. Ok I know this works but its not how I learned it in electronic drafting class. So why after all these years do we need a change? It must be for people that want to prove they know what 5K means without the resistor symbol. 5.7k changed to 5k7 I will never go for that. What does that do save typing space? The new generation learns 5K7 and can not real old circuit drawings that say 5.7K. The rectangle is probably good for he software programs it is easier to make 1 rectangle than all those other symbols.

It reminds me of the story my Aunt liked to tell before she died. She was a RN nurse from the time WWII started until 40 years later. In 1940 when someone was sick at their stomach it was said that they threw up. A few years later someone decided it sounds nicer to say Vomit. A few years later it was changed to Puke. A few years later they said Barf. A few years later it was upchuck. Then it was Whale. About every 5 years the name changed.

gary350 said:

You look at very old electronic drawings capacitors are in MFD. Electric Motors are still MFD. Some where along the way someone changed MFD to uf and pf. I guess it is easier to say .001 uf than .000001 MFD.

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Ackshooly, µF and MFD both mean microfarads (the µ is the Greek symbol for "micron"), so 0.001µF is the same thing as 0.001 MFD.

carbonzit said:

Ackshooly, µF and MFD both mean microfarads (the µ is the Greek symbol for "micron"), so 0.001µF is the same thing as 0.001 MFD.

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Yea......I knew that, I was just testing you. LOL. It was late, past my bed time is made a mistake. Hz is easier some changes are actually better.

gary350 said:

..................
When I learned electronics in college frequency was cycles per second. My Senior year they changed Cycles to Hertz. Why didn't they change it to farts per second. OH.....it has to be names after the old fart that invented it. A 2 meter transceiver was 144 cps then it was changed to 144 Hz. Ok that is rear nice now what!
....................

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The (minor) problem with cps was that people were too lazy to say or write the complete parameter. The would say 100 kilocycles or write 100kc when the correct term was 100 kilocycles per second or 100kcps. There's no such problem with Hz.

Radios with the band dial (AM/FM/SW) marked in wavelength rather than frequency. This was a Blaupunkt Tube car radio that I thought I could find so I could take a pic of.

Here is one: https://www.radiomuseum.org/r/blaupunkt_frankfurt_8.html

A 1950's Magnavox marks the dial as Shortwave MC and Broadcast KC. The Broadcast band is the AM band.

BrownOut said:

Well, we have milli-inches (mills, for more technical types). For example, your circuit board can be 10 inches. To increas by 10%, we can to go 11"". Or if it's 1", we can go to 1.1" No problem at all. The only difference between the systems is the metric has special 'names' for 1/10, 1/100, etc. But we do the same thing with inches, just don't have fancy names. Doesn't change a thing.
...

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Yep I get the point about using "decimalised inches", but I really don't think it comes close to matching the usability of mm.

If you measure the PCB with your decimal inch ruler, the ruler can't show thousandths or hundredths of a inch as they are too small. So the ruler is divided in inches and tenths of inches. Now a tenth of an inch is 2.54mm which is still too big as a measurement for rounding, and wasteful of ruler precision, so they add further divisions at 1/20th inches between the tenths. Now it's more usable as a ruler, but you have a non-standard problem as the other people you may be communicating with might use 3&3/16" while you are measuring to 0.1 or 0.05 inches on the ruler. Not to mention the fact that the 1/20th inch divisions are almost the same size now as mm anyway (surprise!) which is a perfect sized ruler unit. With lines in mm you can see on the ruler a measurement to 0.2mm easily, and for most uses you have ONE number as the measurement as the mm is also about a perfect size for rounding.

Trying to decimalise inches is a bit like putting lipstick on a man! You might really want to believe it makes him "as good as a woman" but once the kissing starts you realise its never going to be the same as the real thing...

Who uses rulers for accurate measurements anyway? If you want any kind of precision, a ruler is the wrong tool for the job. The trick of engineering is to use the proper tool. Rulers are totally inadequate for that kind of precision. Hundreths of inches can be accurately made by using the proper measuring tool. And nobody in engineernig uses fractions.

BrownOut said:

Hundreths of inches can be accurately made by using the proper measuring tool. And nobody in engineernig uses fractions.

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Are you sure?

I guess they do. Look at package dimensions of chips. They usually are given in tenth of millimeters.

1/10mm=.1mm Have you ever seen a package size given as XX&5/16th. No, I didn't think so.

Well, decimals are still fractions in the purest sense, .15 is 15/100. However, the difference is that that all metric measurements are powers of 10 making them easier to work with. I still find mils or thousands of an inch a handy measurement scale. I have a better conception of say 10mil versus .25mm. In any case, I think it's a small tradeoff for the improved overall usability of metric measurements. If all measurements in inches were decimal instead of fractional, I really would not have any complaints about it. But there's also the issue of standardization. Why are we Americans still using imperial measurements when even the country that originated them has switched to SI units. I think we're the only country in the world that hasn't gone metric by now.