Subject: capacitor discharge rate I'm need my math checked! I need to be solve for t in the following rate problem for an electrical capacitor. Vr = E(e^-t/RC), e=nat. log 2.718 raised to the -t/RC power. Every time I do this it comes out different. Thanks for your time. Bill Phillips teacher of Science Hi Bill,
With V _{r} = E e^{-t/RC}V _{r} /E = e^{-t/RC}ln(V _{r} /E) = -t/RCt = -RC ln(V _{r} /E)
There are different ways you can write this which is maybe why you got different answers. _{r} /E)t = -RC (lnV _{r} - ln E)t = RC (ln E - lnV _{r})t = RC (ln E /V _{r})
Harley |