This is an 250mW RF power amplifier project. This circuit is designed to amplify the output of about 7mW wide band FM transmitters to a final level of about 250mW.

Schematic Diagram:

Component Parts:

R1 ____________________ 10R
R2 ____________________ 470R
R3 ____________________ 47R
R4 ____________________ 120R
R5 ____________________ 2K2
R6 ____________________ 4K7
R7 ____________________ 22R
Q1 ____________________ 2N2369
Q2 ____________________ 2N4427
Q3 ____________________ 78L08

C1, C11 _______________ 10n
C2 ____________________ 220u/16V
C3 ____________________ 33p
C4 ____________________ 47p
C5, C6, C7, C8, C9 ____ 1n
C10 ___________________ 10u/25V
L1 ____________________ 5 turn coil
L2 ____________________ 3 turn coil
L3 ____________________ Ferrite
L4, L5, L6 ____________ RFC

This is a simple bridge amplifier based on TDA7240A. This circuit is designed for car audio system, but you may use this circuit for your small home audio application…

Schematic Diagram:

PCB Layout:

Here’s the circuit diagram of a 70W stereo power amplifier which built using single power IC STA550. The circuit is very simple and require little additional electronic components to support the work of IC STA550.

With the features of this IC is owned, produced the audio output will not disappoint.