homework help > electrical engineering > electrical engineering q&a board > topic: rc circuit 2...

Q BgQuestion:

      
Mentor
Karma Points: 716
Respect (100%):
posted by  Zimmy on 10/29/2009 4:46:06 PM  |  status: Closed  |  Earned Karma: 716

RC circuit 2

Course Textbook Chapter Problem Needs by
N/A N/A N/A N/A 11/2/2009 at 8:00:00 AM
Question Details:

A parallel RC circuit has been connected to a voltage source for all time.

R=0.025 Ohms, C= 0.125 farad and  v(t)= 10 sin (5t).

2.1  Derive the current I(t), delivered by the source to the RC circuit as a function of time.

2.2  Convert the above current I(t) to the laboratory form.

2.3  Convert the current to exponential form.

2.4  Derive the average power delivered by the voltage source to the resistor.

2.5 Derive the average power delivered to the parallel element by the source.
An education is just the knowledge to know that you know relatively nothing.
Bonus Point Alert! Earn +7 additional karma points for helping this gold member.

AAnswers:

Answer Question Ask for clarification
Sage
Karma Points: 5,353
(IIT Kharagpur)
posted by Chelsea_fan(MNK) on 11/5/2009 7:59:31 AM  |  status: Live
Asker's Rating: Lifesaver   
Response Details:
it is given, R=1/40 Ω and C=1/8 F....they are in parallel...
so equivalent impedance Zeq=1/40 *1/j*5*8]/[1/40 +1/j*5*8]  =1/40j+40  =[1/40√2]/_-45  Ω

a) current i(t)=v(t)/Zeq=10sin5t/[1/40√2]/_-45   = [400√2/_45]sin5t  A
i(t)=[400√2/_45]sin5t  A
   
i(t)=[400√2/_45]sin5t A



b)again i(t)=[400√2/_45]sin5t

so i(t)=[400√2/_45]*1/_-90 =400√2/_-45 A   since sin5t=1/_-90

i(t)=400√2/_-45 A


c)we know, r/_θ=re^jθ

so i(t)=400√2e-j45 A


d)here ω=5
         2πf=5
         f=5/2π
now time period T=1/f=1/5/2π=1.257 s

as resistor and capacitor are in parallel so voltage drop across them equal to source voltage

so Pavg=1/T

           integrating we get,
Pavg=1965.4W

Pavg=1965.4W

e)the power delivered to parallel element is

Pavg=1/T

integrating we get Pavg=2779.3 W
Pavg=2779.3 W
Answer Question Ask for clarificarion
Ask New Question

Join Cramster's Community

Cramster.com brings together students, educators and subject enthusiasts in an online study community. With around-the-clock expert help and a community of over 100,000 knowledgeable members, you can find the help you need, whenever you need it. Join for free today » How Cramster is different from tutoring »

Need Help In

Useful Links