|
|
|
This thread is locked; no one can reply to it.
|
| How Much is 10 farad? |
|
Billybob
Member #3,136
January 2003
|
It's been too long since physics class. What could this baby power?
|
|
Thomas Fjellstrom
Member #476
June 2000
 |
A lot. The description on the page lists one use. Power a small electronic device for hours. Most caps are rated in milli and micro farad. edit, makes me think, how many mAh can you get out of one of these? -- |
|
miran
Member #2,407
June 2002
|
Yeah, anything above the micro range is quite big and anything above mili is huge. -- |
|
Bob
Free Market Evangelist
September 2000
 |
Quote: makes me think, how many mAh can you get out of one of these? Well, F = C/V, and V = 2.5 Volts, F = 10 Farads, thus C = 25 Coulombs = 25 Amp*seconds = ~6.94 mAh. -- |
|
Goalie Ca
Member #2,579
July 2002
 |
10F cap is a lot! I've always wanted to play with a time constant of longer than a lifetime ------------- |
|
jhuuskon
Member #302
April 2000
 |
That's the problem. The charge and discharge rates in big caps are long as hell, so you might as well as use a battery. Capacitors big in rating still need to be big in size, if one wants them to be any better than just having a regular battery. You don't deserve my sig. |
|
kikabo
Member #3,679
July 2003
 |
I remember our physics teacher saying that the capacitance of the earth is about one farrad when he was trying to emphasize how huge that really is |
|
LennyLen
Member #5,313
December 2004
 |
That cap is a baby! I used to work at a company that manufactured switch-mode power supplies used for telecommunications sites and other industrial uses. The line I worked on produced some of the smaller scale models,and we used several 25F caps in ours. Some of the custom jobs used caps that measured in the 100s. I did visual inspection and rework. The next station after mine was final assemble and live testing, so I was close enough that when one of those blew, my ears would be ringing for minutes afterwards.
|
|
BAF
Member #2,981
December 2002
 |
Quote: The unit of capacitance is a farad. A 1-farad capacitor can store one coulomb (coo-lomb) of charge at 1 volt. A coulomb is 6.25e18 (6.25 * 10^18, or 6.25 billion billion) electrons. One amp represents a rate of electron flow of 1 coulomb of electrons per second, so a 1-farad capacitor can hold 1 amp-second of electrons at 1 volt. A 1-farad capacitor would typically be pretty big. It might be as big as a can of tuna or a 1-liter soda bottle, depending on the voltage it can handle. So you typically see capacitors measured in microfarads (millionths of a farad). To get some perspective on how big a farad is, think about this: * A typical alkaline AA battery holds about 2.8 amp-hours. If it takes something the size of a can of tuna to hold a farad, then 10,080 farads is going to take up a LOT more space than a single AA battery! Obviously, it is impractical to use capacitors to store any significant amount of power unless you do it at a high voltage.
|
|
Goalie Ca
Member #2,579
July 2002
|
Quote: I remember our physics teacher saying that the capacitance of the earth is about one farrad when he was trying to emphasize how huge that really is A traditional capacitor has two plates and maybe an electrolyte in the middle. Capacitance mostly scales with surface area and the constant defined by the substance in between. A super cap has tons and tons of surface area all scrumpled up inside. With nanotubes we're expecting a great increase in the potential. ------------- |
|
relay01
Member #6,988
March 2006
 |
10 farad <= 1 US Dollar
_____________________________________ |
|
Johan Halmén
Member #1,550
September 2001
|
I know what you can do with it. You can attach it to these stupid computer "main" switches so that you don't have to wait only 6 seconds but 6 years before replugging, after unplugging the main, after a crash. What I'm ranting about? When our new machines at work crash, I unplug the main. Then I wait for the green led at the stupid power button to stop blinking. Then I replug and cold boot the machine. As long as the led blinks, the switch logic is in a crash state and the computer doesn't start. With that cap it would probably blink for years. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Years of thorough research have revealed that what people find beautiful about the Mandelbrot set is not the set itself, but all the rest. |
|
Arthur Kalliokoski
Second in Command
February 2005
 |
Quote: The charge and discharge rates in big caps are long as hell I remember reading about the people who experiment with super powerful electromagnets, they need hours to charge several tons of caps (due to power line capacity) but they discharge them in a fraction of a second. They all watch too much MSNBC... they get ideas. |
|
piccolo
Member #3,163
January 2003
 |
yippy portable rail gun here i come.;D edit: wow |
|
Derezo
Member #1,666
April 2001
 |
It's rather frightening to know that other people think like you.. "He who controls the stuffing controls the Universe" |
|
miran
Member #2,407
June 2002
|
Quote: It's rather frightening to know that other people think like you...
I was thinking about the same thing as him. -- |
|
jhuuskon
Member #302
April 2000
|
Quote: I remember reading about the people who experiment with super powerful electromagnets, they need hours to charge several tons of caps (due to power line capacity) but they discharge them in a fraction of a second. Yep, small caps. One big cap wouldn't have discharged that fast. You don't deserve my sig. |
|
Rampage
Member #3,035
December 2002
 |
How big would the explosion be if that thing is reverse-polarized? -R |
|
LennyLen
Member #5,313
December 2004
|
Quote: How big would the explosion be if that thing is reverse-polarized? Not that big, actually. Very loud though.
|
|
Johan Halmén
Member #1,550
September 2001
|
It's rather frightening to know that other people think like me ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Years of thorough research have revealed that what people find beautiful about the Mandelbrot set is not the set itself, but all the rest. |
|
|
Supercaps are cool although i've never played with one meself. And for those doing calculations always look at the datasheet 
