Explore core concepts of RC circuits and their frequency response characteristics with these targeted questions. This quiz covers cut-off frequency, filter types, gain behavior, and phase shifts, helping you assess and expand your understanding of RC filters in electronic circuits.
In a simple RC low-pass filter with a 1 kΩ resistor and a 0.1 µF capacitor, which one of the following is the closest value to its cut-off frequency?
Explanation: The cut-off frequency for an RC circuit is calculated by f = 1/(2πRC). Substituting the given values, f = 1/(2π × 1000 × 0.1×10^-6) ≈ 1,590 Hz. 159 Hz and 100 Hz result from decimal place errors or using the wrong capacitance. 10,000 Hz would require much smaller R or C values, so it is not correct.
Which configuration best describes an RC high-pass filter in terms of component placement relative to the input signal?
Explanation: An RC high-pass filter consists of a capacitor placed in series with the input signal, and a resistor connected from the capacitor's output to ground. The alternative with resistor in series and capacitor to ground is a low-pass filter. Both components in parallel would not yield standard filtering behavior. Two series resistors with output across one forms a voltage divider, not a filter.
When an RC low-pass filter is exposed to frequencies much higher than its cut-off frequency, what happens to the output signal?
Explanation: At frequencies much higher than the cut-off, the capacitive reactance becomes very small, causing the output to be heavily attenuated. The signal is not amplified, so that option is incorrect. The output amplitude matching the input only happens at low or zero frequency. The phase relationship also changes at high frequencies, so it's not always in phase.
For a simple RC low-pass filter, what is the phase shift between input and output voltages at the cut-off frequency?
Explanation: At the cut-off frequency, the output is shifted by 45 degrees relative to the input. Zero degrees occurs only at DC or very low frequencies. Ninety degrees is incorrect, as it occurs only as frequency approaches infinity. One hundred eighty degrees is unrelated to RC low-pass filter phase behavior.
What will be the output of an RC high-pass filter when a DC voltage is applied as an input?
Explanation: A high-pass filter blocks DC, so after the capacitor charges, the output drops to zero volts. The output equals the input only briefly during charging, not steadily. Doubling the input is not possible in a passive filter. Oscillation does not occur in a basic RC high-pass filter with DC input.