Eli5 Why is one Farad an impractically large unit? 1 Coloumb of charge is technically the electric charge of 6.24 10e18 charge carriers. And one Farad is by definition this much amount of charge stored across a potential difference of one volt. If related what are Supercapacitors, their application?
In: 46
A Coulomb is an established unit. For example, “Amps” are Coulombs per second. As much as possible, we want to use established units in their “base” form for building other units. Making a Farad “millionths of a Coulomb per volt” isn’t what we want to do. You can call it a microfarad instead. And we do.
Yes, in the history of capacitors it’s meant that the average capacitor has incredibly *small* amounts of Farads, but that’s just how it goes.
As for “supercapacitors”, they are just capacitors that have reached more than 1 Farads worth of capacitance. And even that’s not an official definition. While not a replacement for a battery, they’re at the point where they can join a battery in dealing with surge demands, such as when a battery is asked to put out hundreds of amps suddenly, perhaps for the starter motor of a car, or a battery backup power supply when commercial power goes out switching to battery power…. poor batteries go from minimal power draw (or even a float charge) to suddenly demanding hundreds of amps produced. Supercapacitors can provide that cushion for the batteries.
Well in terms of modern micro electronics, a Farad is impractical just like an Ampere is rather impractical. They’re both based off the unit of charge (Coulomb). It is just that modern stuff don’t need to move that much charge to work.
But that is more or less a recent phenomenon (recent as in after the invention of the solid state transistor) when things used for control started using an order of magnitude less voltage and orders of magnitude less current compared to the vacuum tube.
If you are working in amps and volts and seconds, which are very common and useful real-world quantities, coulombs and farads give you a 1:1 relationship between those. No need to scale or convert by a factor you’d either need to remember, look up, or approximate. While the farad ratings of common capacitors look complex because they are frequently uf instead of f, the math is much simpler this way.
Can someone eli5 the question?
Michael Faraday pioneered his work in the 1830s. Back then, a lot of science was performed by wealthy people and not so much institutions. The technical equipment was just not available and whatever they used had to be commissioned using craftsmen. That all said, the equipment was just not that sensitive. There wasn’t much history to know how to make them better. To determine relationships and come up with formulas that were accurate, high energy was needed. So the standard derived through testing is quite high. Today’s electronics require much lower energies. So with capacitors, what is used today in useful electronics are often a millionth or million millionth of the derived Farad.
Latest Answers