Maybe you do not believe , because so long radios sold in the form usiong DC power as the driving component work. But I took to fiddling with radio without making a circuit of electrical current/voltage source which is rather strange. Radio Works well if no one put the components in accordance with its placement or its symbol. Therefore , we must consider the placement and and examined before starting step in assembling this very simple circuit.
Description :R1=2K2C1=Varco (variable capacitors ) 0-250 pFC2=100pFD1=Crystal Diode OA72A = Receiver Antenna 10-20 meters alongL1=Spool of wire antenna using nikelin / copper 0.25mm and 12.5mm koker and as 30 rolls wrapped arround to ferit.
The circuit above is only useful as a radio receiver only. Can be called a crystal radio. The diode will process the sound waves through the antenna, then stored to capacitors.