Monday, December 30, 2013

FM Radio Station Sensitivity Part 21

Sensitivity circuit, adjust values as needed
This project installs a sensitivity control to the FM radio station. R1 is a static preset 1K ohm resistor as seen in the original schematic. Add an optional resistance with a 0 to 10K ohm variable potentiometer as shown. The variable potentiometer becomes the sensitivity control. Just dial in the amount required.

Calibrate the sensitivity control based on the sound source to improve the sensitivity and quality of the signal. The microphone will be the most sensitive when the value is at zero ohms. R1 is actually an optional resistor as shown. It's purpose is to limit the voice sensitivity, for example, a 10K resistor will resist the voice signal coming from microphone more as compared to the 1K resistor.