Engineering Board Exam Reviewer · Passive Filters · medium
A filter passes 10 W in its passband. How much power does it pass at the cutoff frequency?
- 7.07 W
- 5 W
- 3.16 W
- 2.5 W
Answer
B. 5 W
Solution
At fc the voltage gain is 0.707, so the power is 0.7072=0.5 of the passband value: 10×0.5=5 W (the -3 dB point is the half-power point).
More Passive Filters questions
- The series RLC band-pass filter shown takes its output across the resistor, with L=10 mH, C=100 nF, and R=100, . Find its bandwidth.
- The series RLC band-pass filter shown takes its output across the resistor, with L=10 mH, C=100 nF, and R=100, . Find its center frequency.
- The gain plot of a first-order RC low-pass filter is shown (the red dot marks the cutoff frequency). If a 3 V rms signal at 10 kHz is…
- The RL high-pass filter shown uses R=470, and L=22 mH. Find its cutoff frequency.
- The RL low-pass filter shown uses R=10 k and L=100 mH. Find its cutoff frequency.
- Find the voltage gain, in decibels, of the RC low-pass filter shown (R=330, , C=100 nF) at 24.1 kHz.
- For the RC low-pass filter shown (R=6.8 k , C=22 nF), by how many degrees does the output voltage lag the input voltage at 3.19 kHz?
- An RC high-pass filter with C=470 nF and R=680, is driven by a 10 V rms sine wave at 124 Hz. Find the rms output voltage.
- An RC low-pass filter with R=470, and C=1, F is driven by a 10 V rms sine wave at 677 Hz. Find the rms output voltage.
- A band-pass filter has lower and upper cutoff frequencies of 8 kHz and 12 kHz. What is its bandwidth?