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 simple 220V light dimmer circuit can be used to adjust the brightness of mains lights. It also can be used to adjust the speed of AC motors. It uses a triac, diac and has a radio-frequency interference (RFI) noise suppression circuit built into it as well.
Schematic diagram:
Component part:
R1 = 10K
R2 = 2K2
R3 = 180K
Potentiometer 250K
C1 = 150nF/400V dipped polyester
C2 = 47nF/630V dipped polyester
C3 = 220nF/250V AC dipped polyester
Triac = 2N6075 or BT136-500D
Diac = HT-32
FUSE 2A or 3A
This is a sound activated switch circuit. It’s will turn on and turn off based on a loud sound such as clapping your hands. You can adjust the sensitivity (how loud of a sound will activate the circuit) from a pin drop to a Mack Truck Horn. Very practical for a variety of projects. Add a relay to turn on a light when your dog barks, or set of a siren when an intruder makes a loud noise.
Here the circuit diagram:
Component Part:
| R1, R5, R16 = 10kΩ R3 = 22kΩ R2, R6, R9, R13 = 220kΩ R4, R10, R12, R14 = 100kΩ R7 = 270kΩ R8 = 4.7MΩ R11 = 1MΩ R15 = 330kΩ R17 = 4.7kΩ P1 100kΩ Trim Pot | C1, C3 = 10nF C2, C4 = 100nF C5, C6, C8, C9 = 1nF C7 = 1μF/16V Electrolytic C10 = 100μF/16V Electrolytic Q1 = 2N3904 Q2 = MPS6531 U2 = 4001 Integrated Circuit U1 4011 Integrated Circuit LED = LED Red MIC = Electret Microphone |
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.
