Posted on May 3, 2017 4289
The L2 coil consists of 50 coils of 1 mm thick enamel wire, wound into a 5 cm diameter drum. RFC2 has an inductance of 29mH and can operate at 600mA.
The variable capacitors C1 and C2 have a capacity of 500 pF each, with thin sheets. Transformer T1 has a primary with a 2.5K resistor. Its power is 6W. Diode D operates at 250V and can withstand 700mA current. The input of the modulator is excited by a crystalline microphone or by any other audio source.