How can I integrate a sinusoidal current in an L-C circuit undergoing resonance?

  • Thread starter Thread starter Ivegottheskill
  • Start date Start date
  • Tags Tags
    Integrate
Click For Summary
SUMMARY

An L-C circuit undergoing resonance exhibits sinusoidal current described by the equation I(t) = I*cos(omega*t). The confusion arises when integrating this function, with some participants mistakenly suggesting I*t*sin(omega*t) as a result. The correct integration leads to I*sin(omega*t)/omega, where omega represents the constant angular frequency. Understanding that I is the current at time t=0 is crucial for accurate calculations.

PREREQUISITES
  • Understanding of L-C circuits and resonance principles
  • Familiarity with sinusoidal functions and their properties
  • Basic knowledge of calculus, particularly integration techniques
  • Concept of angular frequency (omega) and its role in oscillatory systems
NEXT STEPS
  • Study integration techniques for trigonometric functions
  • Explore the behavior of L-C circuits under varying frequencies
  • Learn about the relationship between angular frequency and frequency in oscillatory systems
  • Investigate advanced topics in circuit analysis, such as impedance and phasors
USEFUL FOR

Electrical engineers, physics students, and anyone interested in circuit theory and resonance phenomena will benefit from this discussion.

Ivegottheskill
Messages
11
Reaction score
0
An L-C circuit will undergo resonance, with the current varying sinusoidally, where:
I(t) = I*cos(omega*t)

I keep getting stuck with an answer of I*t*sin(omega*t)

Can't find anything on the standard table of integrals that would indicate this is incorrect

:confused:
 
Physics news on Phys.org
How did you get the answer of I*t*sin(omega*t)
 
I*cos(omega*t)

omega's just a constant then? I'll call it a

I*cos(at)

I's a constant too, so you'll only integrat cos(at)

which should be sin(at)/a

so I*sin(omega*t)/omega?

Other possibility, since I'm not sure myself, is that you can express omega as a function of time, can't you? (2pi*frequency)and frequency is like 1/t or something. I dunno, I think the first way's right

Edit: Wait, I isn't a constant, well whatever, I'll leave this post up here for learning purposes but methinks it's rubbish
 
so I*sin(omega*t)/omega?
That looks correct. I wasn't sure what you were integrating.

omega isn't a funtion of time - it is a constant.

omega is only a funtion of time if it varies with time.
frequency isn't a function of time either, but usually, a constant value. frequency is simply the rate at which something changes wrt time. But that rate of change is constant!
 
schattenjaeger said:
Edit: Wait, I isn't a constant, well whatever, I'll leave this post up here for learning purposes but methinks it's rubbish

That I is a constant - it's the value of the current at time t = 0 (usually).
 
Thanks I'll give that a shot. Sorry for the confusion, omega was a constant (angular frequency). I'm worried about how much high school stuff I've already forgotten :eek:

I wasn't sure how to properly intergrate in that case.

I tried looking it up, but could only find the simple cases (i.e. integrate sin x = cos x)
 
Last edited:

Similar threads

  • · Replies 21 ·
Replies
21
Views
1K
Replies
17
Views
3K
Replies
6
Views
1K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 3 ·
Replies
3
Views
874
  • · Replies 4 ·
Replies
4
Views
2K
Replies
4
Views
943
Replies
12
Views
2K
  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 2 ·
Replies
2
Views
1K