FM TRANSMITTER CIRCUIT WITH CIRCUIT DIAGRAM

FM TRANSMITTER CIRCUIT DIAGRAM

COMPONENTS USED

1.     Micro Phone

2.     10k ohms (3)

3.     50k ohms variable Resistor

4.     1M ohms

5.     100k ohms

6.     1k ohms

7.     66 ohms

8.     0.1uf capacitor (3)

9.     10pf capacitor

10. BC548 Transistor

11.  BF494 Transistor

12.  Antenna

13.  9v DC source

14. Inductor

WORKING PRINCIPLES

The FM Transmitter circuit above has two sections. The first section is a class A Amplifier built around Transistor Q1 (BC548). The second section is very high frequency oscillator circuit built around Transistor Q2 (BF494). The circuit has two inputs (auxiliary input and a micro phone input) which are been balanced by a 50k ohms variable resistor.

The Class A amplifier built around BC548, pre amplifiers the inputs. The output is fed into the input of the very high frequency oscillator. The modulating signal (Audio input) is then modulated by the carrier signal generated by the oscillator. The output which is the modulated wave is fed into an antenna or further Amplified if a high power output is needed before feeding it to an antenna.

FM SIGNAL AMPLIFIER CIRCUIT DIAGRAM

COMPONENTS USED

1.     12V dc SOURCE

2.     Trimmer Capacitors (4)

3.     2.2k ohms resistor

4.     1k ohms resistor

5.     1nf capacitor

6.     0.01uf capacitor

7.     Antenna

PICTURE OF OUR TESTED HARDWARE DESIGN