Which electronic component is commonly used in a receiver to amplify weak signals?

The RF amplifier is a crucial component in a radio receiver because its primary function is to increase the strength of weak signals received by the antenna before further processing. When radio waves enter the receiver, they are often very weak due to distance from the transmission source and other factors. The RF amplifier takes these signals and boosts their amplitude, making them more discernible and easier to work with in subsequent stages of the receiver's circuitry.

This amplification is essential for maintaining signal integrity and ensuring that the receiver can effectively demodulate and decode the information carried by the signals. Without adequate amplification, weak signals may be lost in the noise floor, resulting in poor reception quality.

The other components listed play different roles in the operation of a receiver. A mixer is used to combine signals and shift frequencies. A detector converts modulated signals back into audio or other forms of detectable information. An oscillator generates a waveform used for tuning and frequency adjustment. While all these components are important to the functionality of a receiver, the RF amplifier specifically addresses the need to strengthen weak incoming signals.