9V FM RADIO TRANSMITTER CIRCUIT SCHEMATIC DIAGRAM

9V FM RADIO TRANSMITTER CIRCUIT SCHEMATIC DIAGRAM
The frequency range of this FM transmitter should be about 89MHz – 109MHz. Output power is about 9mW at 9V.

15W TRANSMITTER FM SCHEMATIC DIAGRAM

15W TRANSMITTER FM SCHEMATIC DIAGRAM

This fm transmitter use power transistor BLY88c as the main transmitter amplifier.

CIRCUIT MINI FM TRANSMITTERS SCHEMATIC DIAGRAM

CIRCUIT MINI FM TRANSMITTERS SCHEMATIC DIAGRAM
The supply voltage is between 1.1 – 3 Volts with power consumption is 1.8 mA at 1.5 Volts. This circuit should be able to cover 30 meters of range max. at 1.5 Volts.

FM TRANSMITTER WITH 2 TRANSISTORS SCHEMATIC DIAGRAM

FM TRANSMITTER WITH 2 TRANSISTORS SCHEMATIC DIAGRAM
The coil L1 was consist of 7 turns on a quarter inch plastic former with a tuning slug. The tuning slug is adjusted to tune the transmitter. Actual range on this prototype tuned from 70MHz to around 120MHz. The aerial is a few inches of wire. Lengths of wire greater than 2 feet may damp oscillations and not allow the circuit to work.

CIRCUIT AM TRANSMITTER SCHEMATIC DIAGRAM

CIRCUIT AM TRANSMITTER SCHEMATIC DIAGRAM
The circuit is in two halfs, an audio amplifier and an RF oscillator. The oscillator is built around Q1 and associated components. The tank circuit L1 and VC1 is tunable from about 500kHz to 1600KHz. These components can be used from an old MW radio, if available. Q1 needs regenerative feedback to oscillate and this is achieved by connecting the base and collector of Q1 to opposite ends of the tank circuit.

CIRCUIT 1.5 WATT FM TRANSMITTER SCHEMATIC DIAGRAM

CIRCUIT 1.5 WATT FM TRANSMITTER SCHEMATIC DIAGRAM

P1 act as condenser microphone volume level. For FM, coil will be small. Use thin gauge enamel magnet wire. the diameter of coil will be a couple mm: use ink tube from pen to form, and try 8-12 turns. Small inductance coils make for much guess work.

Components List
R1=220K
R2=4.7K
R3,R4=10K
R5=100ohm C1,C2=4.7uF Electrolytic
C3,C4=1nF
C5=2-15pF
C6=3.3pF Q1=BC547C
Q2=2N2219A
P1=25K
MIC=Electret Condenser Type