Analog and electronic circuits
What is the characteristic of an RC circuit with a capacitor in series with the signal path and a resistor between the output and ground?
- AIt attenuates high frequencies and passes low frequencies
- BIt attenuates low frequencies and passes high frequencies
- CIt passes all frequencies equally
Show answer and explanation
Answer: B. It attenuates low frequencies and passes high frequencies
A capacitor's impedance rises at lower frequencies, so in series it blocks low-frequency signals. This circuit is a high-pass filter that attenuates low frequencies, with the same cutoff frequency as the low-pass filter, 1/(2πRC). It is also used as a coupling capacitor to block DC.