Topic: Analog Circuits
If an input signal with non-zero dc component is applied to a low pass RC network with single resistor R and single capacitor C as shown below, the dc component in the output will be
(The diagram shows $V_{in}$ passing through series R, with C connected in parallel to the output $V_{o}$).
- A. the same as the input
- B. less than the input
- C. more than the input
- D. zero
Answer: A. the same as the input
Explanation: A capacitor acts as an open circuit to DC (frequency $f=0$). Because no direct current flows through the capacitor, there is no voltage drop across the series resistor R for the DC component. Hence, the DC component at the output is the same as that of the input.