TRANSISTOR BASED FM
RECIEVER IN
COMMUNICATION SYSTEMS
PRESENTED BY
TANISHA SUVARNA : 1NT22CS203
PRIYANKA : 1NT22CS148
VISMAYA Y : 1NT22CS215
TRANSISTOR BASED FM
RECIEVER
Introduction
An FM receiver is an electronic device designed to
receive,decode,and reproduce audio signals transmitted
using frequency modulation(FM).FM is a method of
transmitting information by varying the frequency of a
carrier wave, commonly used in radio broadcasting for its
high sound quality and resistance to interference.
COMPONENTS USED
• Transistors- 1 BC547, 1 BC557
• 15pf capacitor
• 8.2 ohm resistor
• 3.3ohm resistor
• 8 ohm speaker
• B10K potentiometer
• 6v Lithium ion battery
• Antenna
CIRCUIT DIAGRAM:
Working Principle
•Signal Reception and Tuning: The antenna captures FM signals, which are modulated in frequency.
The 18pF capacitor and 10K potentiometer form a tuning circuit (LC circuit) that allows the receiver to
select a specific FM station by adjusting the resonance to match the carrier frequency of the desired
station.
•RF Amplification (BC547): The received FM signal is passed to the BC547 NPN transistor, which acts
as a RF amplifier, boosting the strength of the signal for further processing. The transistor amplifies the
weak FM signal received from the antenna.
•Demodulation: The amplified FM signal is sent to the demodulation stage, where the frequency
variations (carrying the audio information) are extracted and converted back into an audio signal. This
process involves detecting the changes in frequency of the FM signal.
•Audio Amplification (BC557): The demodulated audio signal is sent to the BC557 PNP transistor,
which amplifies the audio signal. This ensures the audio is loud enough to drive a speaker or headphone.
•Power Supply and Output: The entire circuit is powered by a 6V battery, which provides the necessary
DC voltage to power the transistors and the rest of the circuit. The amplified audio signal is then sent to
the output device (speaker or headphones) where the audio can be heard.
ADVANTAGES AND DISADVANTAGES
ADVANTAGES:
1.Low power consumption due to the 6V battery, making it portable.
2.Simple and compact design with few components, ideal for beginners.
3.Cost-effective, as the required components are inexpensive.
4.Great for learning and education about FM signal processing.
5.Analog operation avoids the complexity of digital circuits.
Disadvantages:
1.Limited tuning range and may not pick up all FM stations clearly.
3.Lower sensitivity and poor selectivity compared to modern receivers.
4.Audio quality may be lower with more noise or distortion.
5.Manual tuning is required, making it less convenient than digital tuners.
6.Weak audio output, needing external amplification for better sound.
CONCLUSION
A transistor-based FM receiver is a simple, cost-effective, and
energy-efficient solution for basic FM radio reception. While it offers
advantages like low power consumption and ease of learning, its
limitations in tuning accuracy, audio quality, and sensitivity make it
less suitable for high-performance applications. Nonetheless, it
remains a great project for educational purposes and basic FM
signal processing ..
THANK YOU
