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Capacitor Charge Time 
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#1
Jun2214, 03:05 AM

P: 7

Hello all,
I was reading this post on calculating the capacitor charge time:
My problem is i have a capacitor (1000uF) and i want to determine its charge time but dont know the R value, is it something i chose arbitrarily or should it be in a datasheet. Thanks. 


#2
Jun2214, 03:27 AM

P: 107

It should come from the circuit. If your resistance is at or near 0, then your current is very large and your capacitor would fill up instantaneously.



#3
Jun2214, 03:51 AM

P: 7

is there a typical value that i should use, or does that all depend on how much current i want?



#4
Jun2214, 06:03 AM

Sci Advisor
PF Gold
P: 11,923

Capacitor Charge Time



#5
Jun2214, 07:14 AM

Sci Advisor
Thanks
P: 1,766

The critical parameters relating to minimum charge time will be specified in the manufacturers data sheet.
1000uF will almost certainly be electrolytic, so the parameters will be; 1. ESR, the effective series resistance. 2. Ripple current, I_ripple. 3. Temperature rating. If you try to charge an electrolytic capacitor too quickly, the high current flow may fuse the internal foil. That can also happen if you short circuit a capacitor. If you repeat the chargedischarge cycle often, the I^{2}R power dissipated in the capacitor ESR may overheat the electrolyte. Keep the current below the ripple current specified. To charge a capacitor, C, from a fixed DC voltage, V, through a resistor, R, will require the minimum resistor value to be R = V / I_ripple. 


#6
Jun2214, 08:43 AM

Sci Advisor
PF Gold
P: 3,518

here's a pretty good overview of large capacitors
http://www.vishay.com/docs/28356/alu...troduction.pdf 


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