- #1
Haven Barnes
- 5
- 0
Homework Statement
Here is the problem in question. The only values given are those shown on the circuit labels. We are asked to form a voltage equation using Kirchoff's voltage law with specific loops. We were NOT asked to solve the equations for the currents.
Homework Equations
Sum of Voltage in a closed loop = 0.
V = IR
Voltage on an inductor = -L*(di/dt)
V = Q/C
Important equation for my question: I = dQ/dt
The Attempt at a Solution
My solution was this: for loop BCFE, I formed this equation:
-2I3 - I3/7 - 2I3 + 5*dI2/dt = 0
^This equation was marked completely wrong because he wanted Q/7 for the voltage on the capacitor in the diagram.
However, we are not given a value for Q, so I was wondering how having this unknown variable in the equation would help us solve for the currents at all?
When I asked, my professor told me that I was 100% wrong because if I tried to solve for the currents, it would not work. (Which confuses me as Q doesn't seem to be helpful either as we would be left with too many unknown variables).
Here's my attempt at arguing why it is right. I would appreciate any advice/direction on if I am way off or am in the right direction.
My idea is that since I = dQ/dt, this forms a direct relationship between the charge on that conductor and the current we would be trying to solve for. Using a differential equation and some other fiddling I feel that I could argue that this is true
Here is an example of the strategy I'm referring to, however this is used on an AC circuit.
Thank you in advance!