So given electrons are negative, can you have -1C if the charge is negative or positive, or is it an absolute value? Never mind, I saw your answer, the old conventional current vs. electron current raises its ugly head yet again.

I suspect if we ever have antimatter Cu or some other form of antimatter electricity the numbers just flip signs. It is probably useful in some battery chemical reactions where the charge carriers are ions. I can't think of any other examples where the charge carrier is positive.

What I said also applies to ohms law.
I = E / R
1A = 1V / 1Ω
or power
P = E I
1W = 1V * 1A
P = E² / R
1W= 1V² / 1Ω
Values can vary in exactly the same way, different equations, same rules, I think I finally understand now. If I am actually wrong on any points, you have my undivided attention.

I will quibble about t, since seconds are the core part of the definitions, all other units of measurements must be converted to seconds to have a meaningful relation. Years, for example are not exact, they vary over time, as the earths rotation slowly changes and slows down. I am positive the SI definition of seconds is no longer linked to earths orbit or its rotation. Astronomical phenomenon is simply not precise enough for SI units. Have I mentioned my one year stint as a metrology tech for Alcatel?

One of the points I was taught in listening class (Corporations actually have classes like that, I worked for Alcatel ≈ 24 years) is to paraphrase what you hear and restate it, to see if you have it right.

I am about to start a new thread to test my newfound knowledge, How to calculate the freq of a hysteric oscillator/triangle wave generator?

 

So given electrons are negative, can you have -1C if the charge is negative or positive, or is it an absolute value? Never mind, I saw your answer, the old conventional current vs. electron current raises its ugly head yet again.

I suspect if we ever have antimatter Cu or some other form of antimatter electricity the numbers just flip signs. It is probably useful in some battery chemical reactions where the charge carriers are ions. I can't think of any other examples where the charge carrier is positive.

What I said also applies to ohms law.
I = E / R
1A = 1V / 1Ω
or power
P = E I
1W = 1V * 1A
P = E² / R
1W= 1V² / 1Ω
Values can vary in exactly the same way, different equations, same rules, I think I finally understand now. If I am actually wrong on any points, you have my undivided attention.

I will quibble about t, since seconds are the core part of the definitions, all other units of measurements must be converted to seconds to have a meaningful relation. Years, for example are not exact, they vary over time, as the earths rotation slowly changes and slows down. I am positive the SI definition of seconds is no longer linked to earths orbit or its rotation. Astronomical phenomenon is simply not precise enough for SI units. Have I mentioned my one year stint as a metrology tech for Alcatel?

One of the points I was taught in listening class (Corporations actually have classes like that, I worked for Alcatel ≈ 24 years) is to paraphrase what you hear and restate it, to see if you have it right.

I am about to start a new thread to test my newfound knowledge, How to calculate the freq of a hysteric oscillator/triangle wave generator?

Hi there Wendy,

I always ask people to learn nodal analysis. That way they can derive a lot of stuff they want to know about with just a tiny bit more imagination.
I look forward to your new thread and hope i can contribute.

 

So given electrons are negative, can you have -1C if the charge is negative or positive, or is it an absolute value? Never mind, I saw your answer, the old conventional current vs. electron current raises its ugly head yet again.

For completeness, yes you can definitely have both positive and negative charges. Take a capacitor (think of a simple parallel-plate capacitor for simplicity) that has a charge of 1 nC on it. The capacitor as a whole is uncharged, but internally there is a separation of charge between the plates. Now imagine pulling the plates apart and taking one to New York and the other to California. Now one has a charge of +1 nC and the other has a charge of -1 nC. Since you know that the charge is due to excess electrons on one and a deficiency of electrons on the other, knowing whether you have the one that has +1 nC or the one with -1 nC tells you whether you have the one with excess electrons or the one that has a deficiency.

Take a capacitor in which
I suspect if we ever have antimatter Cu or some other form of antimatter electricity the numbers just flip signs. It is probably useful in some battery chemical reactions where the charge carriers are ions. I can't think of any other examples where the charge carrier is positive.

There a many examples. Many processes use ions, such as ion beam epitaxy. Also, many radioactive decay events involve positive charge carriers. Alpha particles are positively charged and so a stream of them is an electrical current. Similarly, positron emissions are currents involving positive charge carriers.

I will quibble about t, since seconds are the core part of the definitions, all other units of measurements must be converted to seconds to have a meaningful relation.

Really?

So the charge capacity of a battery expressed in ampere-hours (current·time) is not meaningful and must be converted to ampere-seconds in order to have meaning?

Years, for example are not exact, they vary over time, as the earths rotation slowly changes and slows down. I am positive the SI definition of seconds is no longer linked to earths orbit or its rotation. Astronomical phenomenon is simply not precise enough for SI units. Have I mentioned my one year stint as a metrology tech for Alcatel?

There are many different definitions of a 'year' (each with a specific name that is usually shortened to just 'year' unless the distinction is relevant).

For instance, there are the Julian year, the Gregorian year, the tropical year, sidereal year, the anomalistic year and many others.

For these types of discussions the year used is almost always the Julian year, which is 365.25 days, exactly, where each day is 86,400 days long, exactly, for a total of 31,557,600 seconds, exactly.

When talking about the variable 't', seconds are not a core part of the definition. This represents the concept of 'time' and it separate from any particular measure of time.

This is no different than a relation such as

W = F·d (Work = Force · distance)

The variable 'd' is distance and is independent of the units used has units of distance. It can be ANY units of distance. It does NOT have to be meters just because the SI unit for distance is the meter. This relationship would be just as valid on another world that had never heard of meters and, similarly, Q=I·t would be just as valid on that same world that had never heard of a second.

 

Really, years are exact?

How about leap years, which include the year 2020 (366 days, not 365). Then there is the occasional leap second that is included in a day by NIST to keep our time pieces in sync with astronomical observations.

Timekeeping, including seconds, was originally invented to track a ships location on Earth's oceans. It was fundamentally linked to astronomy. A second on Earth is about 10' square (Latitude and Longitude). A nanosecond is ≈9". This links into wave lengths of photons. Because so many other definitions were linked to a standard second, there came a time seconds and time had to be disassociated from a tool used in navigation (about 50 +years ago). Now we have clocks with an error less than 1 second over the remaining time left in the foreseeable age of the universe, time frames measured in billions of years. In a billion years or so earth will have lost its moon, and possibly engulfed by the red giant our sun will become. In some ways humans have come a long ways, as far as measurements go. Time will tell if humans in general have any longevity.

A second is one of the measurements the Imperial system and metric system both agree on (I think).

So, a question for those following this thread.How did ships in 18th century reset their clocks time if something happened where their clock lost its time? Not to mention checking its accuracy?

Spoiler

They used the moons of Jupiter as seen through spy glasses of the era, conjuctions and crossing were documented to occur on GMT, and published in astronomical books published for that purpose.

 

Really, years are exact?

How about leap years, which include the year 2020 (366 days, not 365). Then there is the occasional leap second that is included in a day by NIST to keep our time pieces in sync with astronomical observations.

I said that there are MANY different definitions of a year, did I not?

Look up the definition of a Julian year.

Timekeeping, including seconds, was originally invented to track a ships location on Earth's oceans.

Time keeping FAR predates sailing ships -- it predates recorded history.

It wasn't until the mid-18th century that time keeping became a practical means of determining a ship's position at sea.

A second on Earth is about 10' square (Latitude and Longitude). A nanosecond is ≈9".

A unit of time is an area???

A unit of time is a distance???

One second of latitude is approximately equal to 101 ft on the Earth's surface. One second of longitude varies from about that same distance at the Earth's equator down to zero at the poles.

A nanosecond is NOT ~9" (or any other distance). What you are referring to is the length that light travels in one nanosecond. In a vacuum light travels very close to one foot (0.299792458 m = 11.80 inches). Your 9" comes from the speed of propagation of an electromagnetic signal in a typical conductor (very close in the case of RG-8/U 50 Ω coax).

A second is one of the measurements the Imperial system and metric system both agree on (I think).

The Imperial system was brought into conformance with the SI system a LONG time ago. Imperial measures were redefined in terms of SI measures; for instance, the inch is EXACTLY 2.54 cm and the imperial gallon is EXACTLY 4.54609 liters.

 

The fact precision time keepers were invented for the purposes of navigation is a true statement and easily proved(I do not count water clocks and hour glasses as precision), so with that thought in mind it's a fact that latitude is expressed in degrees, minutes, and seconds. So it is not a far reach to understand they also match distances. Expressing a Latitude/Longitude to the nearest second gives you an error of 10 feet. To the nearest minute it's an error of 600 ft or around 0.11 miles. I also took surveying when I was in college. So I have unit distances like miles memorized. Of course since the Earth is an approx sphere, The distances vary depending on whether you are near the equator or a pole. Like it or not, units of Latitude/Longitude are expressed in the same terms of a clock for a reason, because at one time the figured much the same way.

But we have drifted way off topic on my thread, so I am done here.now on to my next project. Getting Constant Current through my thick skull was a challenge, but I think I have it now.

William, I think you have a major fondness for arguing devils advocate, but I like you anyway.

 

The fact precision time keepers were invented for the purposes of navigation is a true statement and easily proved(I do not count water clocks and hour glasses as precision), so with that thought in mind it's a fact that latitude is expressed in degrees, minutes, and seconds. So it is not a far reach to understand they also match distances. Expressing a Latitude/Longitude to the nearest second gives you an error of 10 feet. To the nearest minute it's an error of 600 ft or around 0.11 miles. I also took surveying when I was in college. So I have unit distances like miles memorized. Of course since the Earth is an approx sphere, The distances vary depending on whether you are near the equator or a pole. Like it or not, units of Latitude/Longitude are expressed in the same terms of a clock for a reason, because at one time the figured much the same way.

But we have drifted way off topic on my thread, so I am done here.now on to my next project. Getting Constant Current through my thick skull was a challenge, but I think I have it now.

William, I think you have a major fondness for arguing devils advocate, but I like you anyway.

There is a HUGE difference between claiming that "Timekeeping, including seconds, was originally invented to track a ships location on Earth's oceans," and , "precision time keepers were invented for the purposes of navigation".

Even that last statement is not really accurate. Precision time keepers had long since been developed for scientific, particularly astronomical, purposes but were unsuitable for maritime use because they couldn't tolerate the ship motion and environmental variations. A much better statement would be that precision time keepers for maritime use were invented for the purpose of navigation.

As for the claim that expressing a latitude/longitude to the nearest second gives an error of 10 feet, let's just do the math.

1) The Earth's radius is approximately 3,963 miles at the equator.
2) The circumference of the Earth at the equator (assuming it's a perfect sphere) is therefore ≈24,900 miles.
3) There are 5,280 feet in one mile.
4) The circumference of the Earth at the equator (assuming it's a perfect sphere) is therefore ≈131,473,391 feet.
5) There are 360° in a circle.
6) There are 60' in 1°, thus there are 21,600' in a circle.
7) There are 60" in 1', thus there are 1,296,000" in a circle.
8) Therefore 131,473,391 feet = 1,296,000"
9) Thus result is that ≈101.4455 = 1"

Another way to come at it is that the original definition and intent of a nautical mile was 1 minute of latitude along any longitudinal line on the Earth surface. Since a nautical mile is currently defined as exactly 1,852 meters, which is ≈6,076.12 feet, this means that an arc-second of latitude is ≈101.27 feet.

If insisting that a claim that is demonstrably in error by more than an order of magnitude requires a devil's advocate, then I will proudly wear that title.

While the terms minute and second are used for both time and angular measure, the ties between them have less to do with any equivalence between time and angular measure than it does with the fact that both are holdovers of the Babylonian base-60 number system and a 'minute' was 1/60 of something and a 'second' was 1/60 of a minute -- similar to how we use 'percent' to mean 1/100 of something or 'mil' to mean 1/1000 of something in our base-10 system. In fact, they really aren't even the same names. We have minutes and seconds of time and we have arcminutes and arcseconds of angle. Further highlighting that they are not the same thing in any meaningful way is that it takes the Earth 15 minutes to rotate through 1 arcminute. If they were meant to be the same, wouldn't it make sense that they would have defined an arcminute as the amount of rotation that the Earth underwent in one minute of time? They could have easily done so, but chose not to. The day was already divided into 24 hours (two 12-hour periods with 12 being 'nice' because it is highly divisible) and so the Babylonian divisions were simply applied to the hour. The circle was already 360° (which is also highly divisible) and so the Babylonian divisions were simply applied to the angular degree.

 

In calculating the slope of a charge curve it would be?

v/t =I/C

I is in Amps, C is Farads.

Unless I am mistaken this could be used to calculate the freq of a triangle wave generator. Given that a 555 IC uses 1/3Vcc and 2/3 Vcc as the hysteresis points. I'll be testing this in another upcoming thread.

 

In calculating the slope of a charge curve it would be?

v/t =I/C

I is in Amps, C is Farads.

Unless I am mistaken this could be used to calculate the freq of a triangle wave generator. Given that a 555 IC uses 1/3Vcc and 2/3 Vcc as the hysteresis points. I'll be testing this in another upcoming thread.

That formula works only for constant current -- not the case for the 555.

 

There is a HUGE difference between claiming that "Timekeeping, including seconds, was originally invented to track a ships location on Earth's oceans," and , "precision time keepers were invented for the purposes of navigation".

Even that last statement is not really accurate. Precision time keepers had long since been developed for scientific, particularly astronomical, purposes but were unsuitable for maritime use because they couldn't tolerate the ship motion and environmental variations. A much better statement would be that precision time keepers for maritime use were invented for the purpose of navigation.

As for the claim that expressing a latitude/longitude to the nearest second gives an error of 10 feet, let's just do the math.

1) The Earth's radius is approximately 3,963 miles at the equator.
2) The circumference of the Earth at the equator (assuming it's a perfect sphere) is therefore ≈24,900 miles.
3) There are 5,280 feet in one mile.
4) The circumference of the Earth at the equator (assuming it's a perfect sphere) is therefore ≈131,473,391 feet.
5) There are 360° in a circle.
6) There are 60' in 1°, thus there are 21,600' in a circle.
7) There are 60" in 1', thus there are 1,296,000" in a circle.
8) Therefore 131,473,391 feet = 1,296,000"
9) Thus result is that ≈101.4455 = 1"

Another way to come at it is that the original definition and intent of a nautical mile was 1 minute of latitude along any longitudinal line on the Earth surface. Since a nautical mile is currently defined as exactly 1,852 meters, which is ≈6,076.12 feet, this means that an arc-second of latitude is ≈101.27 feet.

If insisting that a claim that is demonstrably in error by more than an order of magnitude requires a devil's advocate, then I will proudly wear that title.

While the terms minute and second are used for both time and angular measure, the ties between them have less to do with any equivalence between time and angular measure than it does with the fact that both are holdovers of the Babylonian base-60 number system and a 'minute' was 1/60 of something and a 'second' was 1/60 of a minute -- similar to how we use 'percent' to mean 1/100 of something or 'mil' to mean 1/1000 of something in our base-10 system. In fact, they really aren't even the same names. We have minutes and seconds of time and we have arcminutes and arcseconds of angle. Further highlighting that they are not the same thing in any meaningful way is that it takes the Earth 15 minutes to rotate through 1 arcminute. If they were meant to be the same, wouldn't it make sense that they would have defined an arcminute as the amount of rotation that the Earth underwent in one minute of time? They could have easily done so, but chose not to. The day was already divided into 24 hours (two 12-hour periods with 12 being 'nice' because it is highly divisible) and so the Babylonian divisions were simply applied to the hour. The circle was already 360° (which is also highly divisible) and so the Babylonian divisions were simply applied to the angular degree.

Just to clarify, for certain corner cases, timing errors have much less influence in latitude than on longitude.
Taking a fix or just a bearing, for the case of Polaris (the star) could give basically the "same" measurement along the day, provided it is visible during that period. In fact, when navigating in the N hemisphere, Polaris can be used for a quick check of your compass (bearing) or your latitude (fix).
In our Southern hemisphere, there is not a relevant star that close to the respective celestial pole.