AM/FM radio circuit using ULN-2241A and ULN-2283B

The ULN-2241A used in the picture is an intermediate frequency amplifier integrated circuit, and the ULN-2283B is a low-power audio amplifier integrated circuit. The amplitude modulation or frequency modulation function can be realized through the switch S. In the figure, A is connected to the AM switch contact, and A1 is connected to the IF amplifier. A2 is connected to transistor VT2.

Some component specifications:

VD1: AM varactor diode TA314

VT1: Transistor MPS3563, used for FM high frequency amplification

VT2: Transistor MPS3563, used for amplitude modulation converter

T1: Magnetic rod antenna coil, 571uH, turns ratio 17:1, quality factor Q=150

T2: RW0-6A7640BM amplitude modulation heterodyne circuit, turns ratio 11:1, quality factor Q=50

T3: RLCS4A893GO amplitude modulation detector circuit, 256uH, turns ratio 5.4:1, quality factor Q=75

T4: BKAC-K3651HM FM detector circuit, quality factor Q=65

T5: BKACS-K4551A0 FM input circuit, turns ratio 7:1, quality factor Q=90