What is the impedance of a network composed of a
0.1-microhenry inductor in series with a
20-ohm resistor, at
30 MHz?
Specify your answer in rectangular coordinates.
20 +j19
From codygasser:
The impedance of an inductor, specified XL, is found using this equation:
XL = 2 ∗ \(\pi\) ∗ frequency ∗ inductance
XL = 2 ∗ \(\pi\) ∗ 30 MHz ∗ 0.1 uH
XL = 18.85 Ω
Inductive Impedance is imaginary, specified "j" or "i", and it has a positive 90° degree angle, which means it gets added to the real resistance or 20 Ω:
20 + j19 Ω
For more information, please see Ham Radio School site article called Complex Impedance Part 3: Putting It All Together.
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In rectangular coordinates, what is the impedance of a network composed of a
0.1-microhenry inductor in series with a
30-ohm resistor, at
5 MHz?
30 +j3
From codygasser:
The impedance of an inductor, specified XL, is found using this equation:
XL = 2 ∗ \(\pi\) ∗ frequency ∗ inductance
XL = 2 ∗ \(\pi\) ∗ 5 MHz ∗ 0.1uH
XL = 3.14 Ω ohms
Inductive Impedance is imaginary, specified "j" or "i", and it has a positive 90° degree angle, which means it gets added to the real resistance or 30 Ω:
30 + j3 Ω Ohms
For more information, please see Ham Radio School site article called Complex Impedance Part 3: Putting It All Together.
Last edited by markadlerdallas. Register to edit
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In rectangular coordinates, what is the impedance of a network composed of a
10-microhenry inductor in series with a
40-ohm resistor, at
500 MHz?
40 +j31400
From kd9fni:
Zr = 40 ohms
Zl = jwL
Zl = j (500 MHz) ∗ (2 x \(\pi\)) ∗ (10 uH)
Zl = j3140e6 ∗ 10e^{-6}
Zl = j31400 Ω ohms
Ztotal = Zr + Zl = 40 + j31400 Ω ohms
For more information, please see Ham Radio School site article called Complex Impedance Part 3: Putting It All Together.
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In rectangular coordinates, what is the impedance of a network composed of a
1.0-millihenry inductor in series with a
200-ohm resistor, at
30 kHz?
200 + j188
From codygasser:
The impedance of an inductor, specified XL, is found using this equation:
XL = 2 ∗ \(\pi\) ∗ frequency ∗ inductance
XL = 2 ∗ \(\pi\) ∗ 30 MHz ∗ 1 mH
XL = 188 Ω
Inductive Impedance is imaginary, specified "j" or "i", and it has a positive 90° degree angle, which means it gets added to the real resistance or 200 Ω:
200 + j188 Ω
For more information, please see Ham Radio School site article called Complex Impedance Part 3: Putting It All Together.
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In rectangular coordinates, what is the impedance of a network composed of a
0.01-microfarad capacitor in parallel with a
300-ohm resistor, at
50 kHz?***
\[159 - j150\]
For study purposes: the j imaginary is ALWAYS (+) for inductors and (-) for capacitors
Formula for parallel RC circuit calculations can be found at the middle of the linked page
Please see Web Archive Org site for the article Parallel RC Circuits The Circuit
To save time you only need to remember the negative sign and then calculate either the real or imaginary part.
Last edited by justinlb28. Register to edit
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In rectangular coordinates, what is the impedance of a network composed of a
0.001-microfarad capacitor in series with a
400-ohm resistor, at
500 kHz?
400 - j318
From kd7bbc:
\(Z_r = 400\)
\(Z_c = \frac{1}{j\text{wc}}, or \frac{-j}{wc}\)
\(w_C = 500000 \times 2\pi \times 0.001e^{-6}\)
Thus, \[Z_{eq} = Z_r+Z_c = 400 -j318.3\]
For more information, please see Ham Radio School site article called Complex Impedance Part 3: Putting It All Together.
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