Capacitor Question

[Illuminati]

Just have a quick capacitor question.

 

How does one find the amperage of a charged cap. Say if I had 120volt 30 micro farad cap, how would I find the amperage produced if discharged? Another question, what about if there were 5 caps lined up in parallel, then what's the amperage?

 

A formula would be fantastic, I've tried looking online but I can't seem to get a straight answer.

[ecoli]

If it's an RC current supplied by a DC, then I think you'd need to calculate the time constant: http://www.tpub.com/neets/book2/3d.htm

then apply the exponential decay equation.

[YT2095]

look up the word "Coulomb" and get a definition for it, there will be your answer(s), it`s a 2 part answer.

[chitrangda]

to find amperage of 5 caps lined up in parallel find the total capacity of the system...say you have five cap of c capacity the net cap will be 5c.now say u are supplying 250v to it. find the total charge(q=cv) and differentiate w.r.t time you will get amperage.

 

amperage of a charged cap:

differentiate following equation w.r.t time

Q=EC (1-e-t/cr)

colored text is in power.

here t is time

E is battery emf

C is capacitance

r is the resistance of the battery and connecting battery taken together.

Edited May 31, 2008 by chitrangda
multiple post merged

[fatter.than.air]

Here is a site I often reference in such situations:

 

http://www.allaboutcircuits.com/

 

It's more of a textbook, but I've found it quite usefull.

[thedarkshade]

Supposing that you know the frequency, then I assume the question would lie in:

 

[math]I=U\omega C[/math] which is derived from

 

[math]I=\frac{U}{R_C}[/math]

 

[math]I=\frac{U}{\frac{1}{\omega C}}[/math]