How do I modify the final current equation so that...?

Thread Starter

PG1995

Joined Apr 15, 2011
816
Hi

Please have a look on the attachment. My main question is at the end. How do I modify the final current equation so that it adjusts for the discharging up to only 27V? Please help me. Thank you.

The answer given is: 4.5 + 5/6 e^(-t/0.15) mA

Regards
PG
 

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Ron H

Joined Apr 14, 2005
7,014
The time constant is correct, but I can't figure out where that answer came from.
The cap's initial voltage is 32V, and it discharges into 27V through 1.5kΩ. Therefore, the current at t(0)+ is (32-27)/1.5k. Armed with this knowledge, you should be able to write an equation that expresses the current as a function of time.
 
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