Thi circuit is very simple with only one transistor. No need additional active components, but if you want to hear the sound louder, just build another amplifier circuit... :)
| 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 |
More instruction how to build this circuit, visit this page