An LC circuit with L = 1 mH must resonate at 50 kHz. Find the capacitance C in nF.
LC resonance, Q factor & bandwidth worksheet with answers
1.Easy
L = 1 mHf0 = 50 kHz
C = nF
2.Easy
A 1 nF capacitor charged to 10 V is switched across an ideal 10 µH inductor. Find the peak current Imax in the circuit, in mA.
C = 1 nFV0 = 10 VL = 10 µH
Imax = mA
3.Medium
A series RLC circuit has R = 10 Ω, L = 470 µH and C = 2.2 nF. Find its quality factor Q.
R = 10 ΩL = 470 µHC = 2.2 nF
Q =
4.Medium
A 4.7 nF capacitor charged to 15 V oscillates with an ideal 470 µH inductor. Find the energy WL stored in the inductor at the moment the capacitor voltage is 3.75 V, in nJ.
C = 4.7 nFV0 = 15 VvC = 3.75 V
WL = nJ
5.Hard
A series resonant circuit uses a 22 µH inductor. Which total series resistance R gives a bandwidth of 100 kHz?
L = 22 µHBW = 100 kHz
R = Ω
6.Hard
A series resonant circuit uses a 4.7 mH inductor. Which total series resistance R gives a bandwidth of 500 Hz?
L = 4.7 mHBW = 500 Hz
R = Ω
Answer key
- 1. C = 10.13 nF
- 2. Imax = 100 mA
- 3. Q = 46.22
- 4. WL = 495.7 nJ
- 5. R = 13.82 Ω
- 6. R = 14.77 Ω
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