Electrical Engineering - RC Circuits - Discussion

Discussion Forum : RC Circuits - General Questions (Q.No. 19)
19.
In a series RC circuit, when the frequency and the resistance are halved, the impedance
doubles
is halved
is reduced to one-fourth
cannot be determined without values
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
6 comments Page 1 of 1.

Joesmarti said:   3 years ago
Z = R - jX.
R' = 0.5 R.
X' = 1 / 2* π*C*(0.5)f = 2X.
Z' = 0.5R - j2X.

Assuming R = 1 and X = 1.
|Z| = √(1^2+1^2) = 1.414.
|Z'| = √(0.5^2+2^2) = 2.0615.

Noor ul islam said:   7 years ago
z =√((2R)^2+(2/wC)^2) because resistance is double and frequency is half.
z = 2√((2R)^2+(2/wC)^2).
So the impedence is double.

Manish said:   8 years ago
There is no explanation about capacitance so without value of capacitance we can't say anything.

Dhaval said:   8 years ago
Here, Z=R+Xc.

Now resistance and frequency is halved so R become R/2 and Xc=1/2π(f/2)c => 2Xc=1/2πfc.

Z'=R/2+ 2Xc so impedance neither double nor halved. So, It cannot determine without values.

Anonymous said:   9 years ago
Please Given the explanation.

ANAND said:   1 decade ago
Total impedance= R-JXc.

Post your comments here:

Your comments will be displayed after verification.