- #1
planck42
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Homework Statement
Solve the differential equation [tex]R\frac{dq}{dt} + \frac{q}{C} = v_0[/tex]
R is resistance, q is charge, t is time, C is capacitance, and [tex]v_0[/tex] is the EMF of the power supply.
Homework Equations
First-order linear differential equation solving method
The Attempt at a Solution
This is a first-order linear differential equation, so let's apply the standard steps to solve it. First, I calculated the integrating factor to be [tex]e^{\frac{t}{RC}}[/tex]. Upon multiplying through by this factor and integrating, I got [tex]\frac{dq}{dt}e^{\frac{t}{RC}} + qe^{\frac{t}{RC}}[/tex] on the left side, and [tex]\int{\frac{v_0}{R}e^{\frac{t}{RC}}[/tex] on the right side. This integrates to [tex]v_{0}Ce^{\frac{t}{RC}}[/tex], neglecting the arbitrary constant. So [tex]qe^{\frac{t}{RC}}=v_{0}Ce^{\frac{t}{RC}}[/tex], which simplifies to [tex]q=v_{0}C[/tex], an unsurprising but disappointing result since I'm trying to find q in terms of time. Perhaps there is something wrong with one of my steps? This has been bugging me for quite some time and I would appreciate a kick in the right direction.