Engineering How Do You Calculate Current and Energy Decay in a Source-Free RL Circuit?

  • Thread starter Thread starter juicev85
  • Start date Start date
  • Tags Tags
    Circuits Source
AI Thread Summary
To calculate current and energy decay in a source-free RL circuit, the initial energy stored in the inductor can be used to find the initial current. The energy stored in an inductor is given by the formula E = 0.5 * L * I^2, allowing for the calculation of current from the initial energy of 100mJ. Once the initial current is determined, the current at t=1s can be found using the formula I(t) = I(0)e^(-Rt/L). Additionally, the remaining energy in the inductor at t=2s can be calculated using the current at that time. Understanding these concepts is crucial for solving the given homework problem effectively.
juicev85
Messages
13
Reaction score
0
We just started source free RL circuit analysis in my circuits class (very easy).
However there is a problem in the HW I am not quite sure how to solve.

Problem: The circuit shown consists of a resistance R = 1 ohm and an inductance l = 2H. At t=0, the inductance is storing 100mJ of energy. Calculate (a) i at t=1s (b) the energy remaining in the inductance at t = 2s.

I can easily solve the problems that give an initial current at t = 0s, but i am not sure about the joules. I know joules are watts/second is there some kind of conversion I can perform to get the current so I can use the I L(t) = 2e^-Rt/L formula. This is an easy problem it just comes down to the fact that the prof. didn't mention anything like this in the lecture. So if you guys can give me the tools I am sure I can solve it.
 
Physics news on Phys.org
There is a formula for the energy stored in an inductor - it depends on L and I. Check that out in your notes or textbook and use it to find the initial current.
 
It would help if the circuit was shown.


BTW - joules are watt-seconds, or watts (W, power) = Joules (energy)/second
 

Similar threads

Engineering How to determine circuit components of ´Mystery Box’ ?
Replies
4
Views
1K
Engineering Find di/dt and dr/dt for a DC circuit with indepedent current source
Replies
3
Views
4K
Engineering Step response of RC circuit with independent voltage and current sources
Replies
7
Views
3K
Engineering Voltage and current calculation of circuit
Replies
5
Views
2K
How to find the current and voltage in a circuit with current sources?
Replies
3
Views
3K
Current flowing through resistor in RLC circuit (C in parallel with L)
Replies
19
Views
3K
Engineering How to deal with dc source on ac circuits?
Replies
7
Views
3K
Engineering Norton/Thevenin Equivalent circuits with a dependent voltage source
Replies
9
Views
5K
How to determine drain-source voltage for this MOSFET amplifier.
Replies
0
Views
2K
Calculating the voltage in an OP-amp circuit with a current source
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top