Hello Everyone, thought you all would enjoy this simple FM radio receiver I made recently. This circuit is simple and works well.
Find more info on the basis for this circuit and the "one transistor radio" from Andy Mitz on his website by clicking here.
Click image for expanded view.
C2, 3-36pF variable capacitor
C3, 1nF ceramic disc capacitor
C4, 20pF ceramic disc capacitor
C5, 4.7nF ceramic disc capacitor
C6, 220nF polyester film capacitor
C7, 2.2nF ceramic disc capacitor
C8, 220uF electrolytic capacitor
C9, 100uF electrolytic capacitor
L1, see note**
L2, see note**
L3, 24uH choke, see note**
R1 and R8, 1k ohm carbon film resistor 1/4 Watt
R2, 10k ohm carbon film resistor 1/4 Watt
R3, 15k ohm carbon film resistor 1/4 Watt
R4 and R5, 470k ohm carbon film resistors 1/4 Watt
R6, 180 ohm carbon film resistor 1/4 Watt
R7, 34 ohm carbon fil resistor 1/4 Watt
Q1, MPF102 N channel JFET
IC1, 431AZ adjustable precision shunt regulator
D1, 1N4001 general purpose rectifier diode
D2, 3mm green LED
SPK1, small speaker or head phones
SW1, SPST switch
L1 and L2 were made by wrapping three tight side by side loops around a sharpie marker, I also made L2 by wrapping about 8 inches of 35AWG magnet wire around a ferrite core, careful to make the windings side by side and glued it in place with a hot glue gun, you can use any 20-30 uH RF choke though, you don't have to make your own.
C1 was removed from the circuit after doing some experimenting so that is why the capacitors part numbers start at C2.