Electronic conventions I hate

[carbonzit]

Yes but it is not used.

Well, duh. We already know that.

 

[KeepItSimpleStupid]

What's "mega"? It's megohms, not megaohms [sic]

 

[4pyros]

Well, duh. We already know that.

OK than thats the answer to this;

Or what about the relationship between 'C:watts? Surely that's worth a lot in electronics.

 

[carbonzit]

Well, duh. We already know that.

OK than thats the answer to this;

Or what about the relationship between 'C:watts? Surely that's worth a lot in electronics.

Still no relationship; why do you keep supposing there is one? The choice of temp. measurement system (C or F or K or ...) is completely arbitrary.

Unless you can show that there's some fundamental physical or mathematical relationship between °C and watts, just accept that it's that way because it's that way.

 

[DerStrom8]

Still no relationship; why do you keep supposing there is one? The choice of temp. measurement system (C or F or K or ...) is completely arbitrary.

Unless you can show that there's some fundamental physical or mathematical relationship between °C and watts, just accept that it's that way because it's that way.

Carbonzit, if you really think about it, EVERYTHING HAS A RELATIONSHIP TO EVERYTHING ELSE in this world. Nothing is truly arbitrary--one thing is always caused by another, and there is no way around that.

There is this formula which indirectly relates watts to degrees, it just requires some other variables as well:

ΔQ = mcΔT

Where Q is the energy in Joules (converted from watts--again, a few other variables are needed), m is the mass, c is the "specific heat" (amount of heat required to raise the temperature of a material by one unit of temperature, relative to another material) of the substance that is being heated, and T is the temperature in Celsius. And of course, Δ is 'delta', meaning 'change'.

 

[CraigHB]

All systems of measurement are arbitrary. It's only a matter of reference. Watts and horsepower contain the same dimensions (mass, acceleration, distance, time) just different scales of measurement. However, the main thing SI units have over imperial is they are decimal instead of fractional. Makes them easier to work with. When you start quantifying things in mils or thousandths of an inch, that's an attempt to decimalize a fractional system. Decimal units are just a more natural thing to work with. I think the big problem with us Americans is what we are used to. For an American, it's easy to mentally gage inches and feet in your head, not the case for centimeters and meters.

 

[carbonzit]

There is this formula which indirectly relates watts to degrees, it just requires some other variables as well:

ΔQ = mcΔT

Where Q is the energy in Joules (converted from watts--again, a few other variables are needed), m is the mass, c is the "specific heat" (amount of heat required to raise the temperature of a material by one unit of temperature, relative to another material) of the substance that is being heated, and T is the temperature in Celsius. And of course, Δ is 'delta', meaning 'change'.

Butbutbut ... if you change your "c", it'll work just as well for Fahrenheit as for Celsius. So there's still no natural connection of any kind between °C and W.

 

[DerStrom8]

Butbutbut ... if you change your "c", it'll work just as well for Fahrenheit as for Celsius. So there's still no natural connection of any kind between °C and W.

The first part of that, I agree with--you can change it to work with either C of F. The second part I would have to take issue with, though--There is a natural connection between watts and temperature (whether C, F, or K). It's all connected.
I am not trying to put in an argument for any specific unit of measurement here. I'm simply saying that there is a calculable relationship between temperature and watts.

 

[Bob Scott]

I like the euro way of marking values as 4K7 etc.

I like the euro way of marking transformer winding direction with a dot.

I understand all of the standards, European, American, or Japanese schematics symbols. I prefer Japanes polarised cap symbols, and also prefer Japanese transistor symbols with the xistor inside a circle.

I like conventional current flow, but I can still imagine the electrons in a tube moving from cathode to plate. Propagation moves from the point of change, whether it occurs in a power supply lead or a return lead. ie: the speed of light change can move from - to +, or + to -.

I like the metric system.
Who cares how many rods there are in a furlong?

Units of conductance? I still like the Mho. I woudn't get caught in a conversation about Seimens. Some casual passer-by overhearing it might not understand.

If you don't like a particular convention, don't gripe about it. Nobody likes listening to a whiner.

 

[Mr RB]

Heat sinks are rated by their thermal resistance (Rth) in °C/W.

Yep, and not just heatsinks. I can't remember seeing any electronics datasheets where the specs or charts discussed anything in 'F/W. But there's usually some chart of 'C/W or 'C/A etc.

A calorie raises 1 gram of water by 1'C. Is there there an energy unit that uses Fahrenheit?

Fahrenheit is not really a proper scientific unit for working with temperature it's a "consumer unit", and only in a couple of countries that haven't quite caught up yet.

If you don't like a particular convention, don't gripe about it. Nobody likes listening to a whiner.
...

Aww, spoilsport! Anyway, isn't this supposed to be a thread for whiners?

 

[carbonzit]

Fahrenheit is not really a proper scientific unit for working with temperature it's a "consumer unit", and only in a couple of countries that haven't quite caught up yet.

So just how is Celsius a more "scientific" scale than Fahrenheit?

Oh, gosh, it must be ... because 0°C is the freezing and 100°C the boiling point of water. That's soooo scientifical.

Isn't that just as anthropocentric as how all the SI-pushers claim the inch and foot are so ridiculous, since they're based on the size of the king's thumb and foot?

Face it; they're both arbitrary. And as Carl has pointed out, °F are actually better suited to what you condescendingly call "consumer" use, as it has more resolution than °C.

 

[misterT]

So just how is Celsius a more "scientific" scale than Fahrenheit?

Oh, gosh, it must be ... because 0°C is the freezing and 100°C the boiling point of water. That's soooo scientifical.

All fahrenheit meters are calibrated using the celsius scale (calibrated celsius meters). How would you define the fahrenheit scale and calibrate a meter using that definition?

Isn't that just as anthropocentric as how all the SI-pushers claim the inch and foot are so ridiculous, since they're based on the size of the king's thumb and foot?

SI-units are accurately defined. If you loose all imperial measuring devices, how could you measure 1 foot?

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[geraldfryjr]

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[geraldfryjr]

Regarding that, the capacitor with the curved bottom should only be used for electrolytics:

**broken link removed**

is for non-electrolytics, and

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should be reserved for electrolytic (i.e., polarized) capacitors.

The curved plate symbol was derived from the days of when tube circuitry was king,it represents the movable plates of a variable (air) capacitor which should always be grounded as to not electrocute the operator from the high voltages thru the tuning shaft.


jer

 

[carbonzit]

**broken link removed**

Your answer is a typical fallacy used in argument. I don't know the exact name of it, but it's basically arguing that since more people adhere to proposition X than proposition Y, proposition X must be correct.

Actually, the chart itself is a fallacy (and if you don't believe me, I invite you to read any of Edward Tufte's works, like his definitive The Visual Display of Quantitative Information). What does the variation in the units that compose a measure have to do with anything? This is just BS tarted up in a chart to make it look authoritative.

 

[DerStrom8]

Your answer is a typical fallacy used in argument. I don't know the exact name of it, but it's basically arguing that since more people adhere to proposition X than proposition Y, proposition X must be correct.

Actually, the chart itself is a fallacy (and if you don't believe me, I invite you to read any of Edward Tufte's works, like his definitive The Visual Display of Quantitative Information). What does the variation in the units that compose a measure have to do with anything? This is just BS tarted up in a chart to make it look authoritative.

The metric system allows for more precise and easily-calculable conversions from one unit of (for example) length to the next. That is what this chart is representing. The base ten system is much easier to learn, use, and convert than the old cr*ppy imperial system. IMHO, there is no real reason why we (Americans) should not switch over to metric. In my views, the imperial system is utterly useless.

Der Strom

 

[carbonzit]

Nobody uses yards to a mile. Therefore, we can eliminate the number 1760 from contention.

That leaves the numbers 3, 12, and 16. Anyone who can't remember these simple numbers and how they relate to measurements is an idiot anyhow. So no, we don't need the crutch of a system where everything is based on 10.

(Just to be clear, I'm referring to measurements used in everyday ordinary life here. Obviously the SI system has great utility in technical applications. I'm not proposing that EEs revert to Imperial measurements. It's a matter of what measure or scale is appropriate to the application.)

 

[DerStrom8]

Nobody uses yards to a mile. Therefore, we can eliminate the number 1760 from contention.

So you'd rather just remember 5280 feet in a mile? What kind of figure is that????

That leaves the numbers 3, 12, and 16. Anyone who can't remember these simple numbers and how they relate to measurements is an idiot anyhow. So no, we don't need the crutch of a system where everything is based on 10.

But why make it more complicated than it needs to be? Wouldn't you rather remember just one neat, even number (10)? And 3, 12, and 16 don't relate to each other nearly as neatly as 1, 10, 100, etc. It's just making it more complicated.
And that brings us to the main point--Why hasn't the U.S. switched to metric when pretty much the rest of the world has? Again, we're just making things difficult--we constantly have to translate kilometers to miles, meters to feet, inches to centimeters, etc. etc. etc. and vice versa. We're the minority right now, meaning it would be easier for us to switch to metric than it would be for the rest of the world to switch to imperial (even if it was worth switching to in the first place). We're doing nothing but over-complicating measurements, and if there are any conventions that I hate, it's the imperial system.

Der Strom

 

[Sceadwian]

Fahrenheit is not really a proper scientific unit for working with temperature it's a "consumer unit", and only in a couple of countries that haven't quite caught up yet.

And probably never will. I've been personally trying to convert to Meter/C for years, it's just too ingrained what to expect. The closest I've gotten is metres, and that's only because I can roughly mentally convert it, I have no inherent sense of the length of a meter.

Hmm... You just brought a thought to mind that may help me though. Never dawned on me before, I've always had a problem with the American fractional system for inches/feet etc... doing household construction I think the solution of that 'inherent' understanding would be to buy myself a Metric tape measure.

 

[KeepItSimpleStupid]

2.5 cm per inch is a known conversion. 1 meter is "about" 3 feet.

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.

A metric tape measure would be really wierd in construction since studs are 16" o.c. or even 24 inches o.c. You won't have those tic marks on a metric tape measure.

I learned the hard way, I ordered proximately 3x as much wire I needed, the feet/meter thing.