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Electrical circuit help


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Guest richardcates
Posted

:confused: I need help with a question and wonder if anyone can point me in the right direction.

 

Two capacitors of 20 microfarad's and 40 microfarad's are connected in series. A constant voltage of 50 V is applied to the combination, it is then removed and replaced with a short circuit. Determine the final charge on each capacitor ?

Posted
:confused: I need help with a question and wonder if anyone can point me in the right direction.

 

Two capacitors of 20 microfarad's and 40 microfarad's are connected in series. A constant voltage of 50 V is applied to the combination' date=' it is then removed and replaced with a short circuit. Determine the final charge on each capacitor ?[/quote']

Are you sure you worded the question correctly?

Posted

Maybe your question has been stated wrongly.

As YT2095 siad, the final charge left on each capacitor will be zero after you leave the circuit for at least a few time constants (After the transient effects have dissipated).

 

This is because all the charge will have been dissipated by through the short-circuit link.

Posted

it would be different if the "Short" was a fixed resistance, and a time index was given :)

 

edit: I`ve had a look around for you, and figure this maybe helpfull to you, rather than me trying to explain it text.

the part at the bottom will be the most applicable I recon :)

http://www.eatel.net/~amptech/elecdisc/capacitr.htm

 

Double edit, the graphs are for charging sure, but apply equaly to the discharge, just reverse the curve :)

Posted
Maybe your question has been stated wrongly.

As YT2095 siad' date=' the final charge left on each capacitor will be zero after you leave the circuit for at least a few time constants (After the transient effects have dissipated).

 

This is because all the charge will have been dissipated by through the short-circuit link.[/quote']

Sorry, I thought the answer was obvious.

 

BTW, a 20 µf capacitor would likely be tantalum, so without the short, the charge would be zero in a short period of time through dielectric absorption.

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