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 very simple FM receiver which build based on one transistor only. No chip or another active component. The output is connected to earphones, you need an amplifier circuit if you want to listen the radio with a loudspeaker.
| Part designator | Part description |
| C1a,C1b | 10 pf, 50 v, ceramic disc capacitor |
| C2 | 22 pf, 50 v, ceramic disc capacitor |
| C3 | RF tuning capacitor |
| C4 | 330 pf, 50 v, ceramic disc capacitor |
| C5,C8 | 0.001 uf, 50 v, ceramic disc capacitor |
| C6 | 0.22 uf, 50 v, film capacitor |
| C7 | 0.0047 uf, 50 v, ceramic disc capacitor |
| C9 | 22 uf, 16 v, electrolytic capacitor |
| D1 | TL431AIZ voltage control Zener (shunt regulator) |
| EPH1 | High impedance earphone |
| L2 | 22 uh RF choke |
| Q1 | 2N4416A JFET transistor |
| R1 | 470K, 1/4 w, resistor |
| R2, R3 | 1K, 1/4 w, resistor |
| R4 | 10K, 1/4 w, resistor |
| R5 | 1M, 1/4 w, resistor |
| R6 | 100 ohm, 1/4 w, resistor |
| S1 | Small SPST switch |
| screws for C3 | screws for mounting C3 (2 needed) |
| nylon screw | #4 nylon screw used for tuning C3 |
| battery connector | mini battery snap |
This is the circuit diagram of mini FM received that build based on single FM IC TDA7012T.
Component Parts List:
| R1 = 8kΩ2 R2 = 10kΩ R3 = 390Ω C1,C3 = 10nF C2,C6,C9,C16 = 100nF C4 = 33pF C5 = 25pF trimmer (Murata type TZB4Z250AB10R00) C7,C10 = 1nF5 C8 = 820pF | C11 = 1nF C12 = 68pF C13 = 220pF C14 = 47μF 10V (Nichicon UWX1A470MCL1GB 5.5mmL chip type) C15 = 3nF3 L1 = 36nH (4 turns 0.5mm silver-plated wire, inside diameter 4mm; length 7mm) L2 = 1μH, SMD case 0805 (fres > 300 MHz) IC1 = TDA7021T (SMD in SO16 case) |
