Question

In a superheterodyne receiver, a stage before the IF amplifier has a variable capacitor in parallel with a trimmer capacitor and an inductance. The variable capacitor is for:

a) Image rejection
b) Tuning
c) Amplification
d) Demodulation

Answer 1

The variable capacitor in the stage before the IF amplifier in a superheterodyne receiver is used for tuning to the resonant frequency of the desired radio station.

Step-by-step explanation:

In a superheterodyne receiver, the stage before the IF amplifier that includes a variable capacitor in parallel with a trimmer capacitor and an inductance is crucial for selecting the correct frequency to which the receiver is tuned. The correct answer to the student's question is that the variable capacitor is used for tuning. Tuning is necessary for the radio receiver to have the same resonant frequency as the carrier wave to pick up the signal while rejecting other frequencies. By adjusting the variable capacitor, users can change the resonant frequency of the RLC circuit, which allows the receiver to tune into different frequencies or stations.