250mW RF Power Amplifier

This is an 250mW RF power amplifier circuit project. This circuit is designed to amplify the output of about 7mW wide band FM transmitters to a final level of about 250mW. General purpose 12V DC power supply can be used to operate this RF amplifier circuit.

Schematic Diagram:

250mW Power Amplifier circuit diagram

Components List:

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 electronic circuit is a simple 2-transistor VHF power amplifier, with about 16dB gain, and requires no tuning or alignment procedures. Wideband techniques have been used in the design and the circuit is equipped with a “lowpass” filter to ensure good output spectral purity. The project has been designed for assembly on a single-sided printed circuit board. The circuit is specifically designed to amplify the output of 7mW to 10mW WBFM transmitters (wide band) to a final level of 250mW to 300mW, after the filter.

The kit of this power amplifier circuit is available at kitsrus.com. You may download the kit manual including the information of schematic diagram, components list, and circuit works from the following link:


250mW RF Power Amplifier Kit


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