Most power supply designers also look at the AC resistance or ESR at 120Hz and 20Khz, and the lifetime at say 85C or 105C.
The lowest ESR often comes from putting a few large, but not huge, caps in parallel. Doubling the Farads often just reduces the ESR by 20%. Low ESR allows large transisents with little voltage droop.
You should also consider the Lifetime. The computer grade capacitors can have 5,000 - 10,000 hours at 85C. The 1 Farad auto capacitors may not be as robust or be able to remove internal heat as easily as a lower storage density computer grade design.
The lowest ESR often comes from putting a few large, but not huge, caps in parallel. Doubling the Farads often just reduces the ESR by 20%. Low ESR allows large transisents with little voltage droop.
You should also consider the Lifetime. The computer grade capacitors can have 5,000 - 10,000 hours at 85C. The 1 Farad auto capacitors may not be as robust or be able to remove internal heat as easily as a lower storage density computer grade design.
moving_electron said:I would imagine a 1F capacitor would be extremely dangerous when not fully discharged. I image it can discharge extremely large currents is accidentally touched.
Course that is not to say a 10,000uF cap cannot kill you.
Depends on the operating voltage.
You can touch with your hands on the terminals of an 100A 12V car battery and nothing happens.
We humans only get an electrical shock at around 60~70 volts and up.
carlosfm said:
Depends on the operating voltage.
You can touch with your hands on the terminals of an 100A 12V car battery and nothing happens.
We humans only get an electrical shock at around 60~70 volts and up.
Wouldnt be so sure... amps kill too, a car battery can provide quite a few of those, more than enough for sure death, you just need enough voltage to cross the skin which is a bad conductor.
We are building six monoblock amplifiers over in this thread:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=43204&perpage=10&pagenumber=29
Each amplifier has a littlle more than 1 Farad at 200V
Here is a link to a photo of the capacitors we'll be using:
http://photonlogic.com/PicServe/Capacitors/WallOfCaps.jpg
Each of those blue cans is 3" in diameter and 9" tall.
-Casey Walsh
http://www.diyaudio.com/forums/showthread.php?s=&threadid=43204&perpage=10&pagenumber=29
Each amplifier has a littlle more than 1 Farad at 200V
Here is a link to a photo of the capacitors we'll be using:
http://photonlogic.com/PicServe/Capacitors/WallOfCaps.jpg
Each of those blue cans is 3" in diameter and 9" tall.
-Casey Walsh
Super Capacitor :
Part Number FB1E505Z
Max. Rated Voltage Operating Temperature
24V (DC) Nominal
Capacitance 5Farads
ESR 500mÙ -40°C to +85°C
http://www.nec-tokin.com/english/product/supercapacitor/application02.html
approx $= 1200/- $
Application: [Automotive engine start-up assist]
Part Number FB1E505Z
Max. Rated Voltage Operating Temperature
24V (DC) Nominal
Capacitance 5Farads
ESR 500mÙ -40°C to +85°C
http://www.nec-tokin.com/english/product/supercapacitor/application02.html
approx $= 1200/- $
Application: [Automotive engine start-up assist]
DigitalJunkie said:
- 100 Farad Storage (that's no typo - 100,000,000µF)
- 16 Volt Rating, 20 Volt Surge
- Ultra low ESR < 0.0018 Ohms. +/- 20% Tolerance
wow
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