Which component in FM receivers is used to apply the AFC DC control voltage?

In FM receivers, a varactor diode is utilized to implement Automatic Frequency Control (AFC). The varactor's ability to change its capacitance when a DC voltage is applied allows it to be used effectively in tuning circuits. By applying the AFC DC control voltage to the varactor, the circuit can adjust the resonant frequency of the tuning circuit automatically. This ensures that the receiver remains locked onto the desired frequency despite any shifts that might occur due to changes in the signal or other environmental factors.

This capacity for continuous adjustment is crucial in FM reception as it helps maintain a stable and clear signal. The varactor effectively helps in minimizing the effects of frequency drift by dynamically altering the tuning characteristics of the circuit, ensuring optimal reception of the broadcast.