Sunday, April 21, 2024

88.00MHz-108.00 MHz FM Radio Receiver Using AN 7223

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Here is a simple FM radio receive which is built around 18-pin IC AN 7223. You can tune to frequency around 88.00MHz-108.00Mhz from this FM radio receiver.AN 7223 can be easily purchase in a market and it cost is not expensive. Most FM radio was works on 10.7MHz IF frequencies and uses 10.7MHz IFT coil and 10.7MHz Ceramic filters. As a 10.7MHz IFT coils are not found easily. So, here i use 5.5MHz IFT coil and 5.5MHz ceramic filter which can be easily available.

Circuit Description

Only one NPN transistor BF494 and one Intergrated circuit AN 7223 (18-pin) are used in this circuit. Few external components like coil, 5.5MHz IFT coil,5.5MHz ceramic filter, resistors, ceramic capacitors, trimmer capacitor (2-22pF) were used.

Capacitor C1 (100uF/25V) is connected to ground with its negative terminal and positive terminal to pin 5. Capacitor C2 (4.7uF) is also connected to ground with a negative terminal and positive terminal to pin 6 of AN7223.

Capacitor C3 (203) is connected between pin 8 and pin 9 of AN 7223.Capacitor C4 (203) is connected to pin 9 of AN7223 and ground. Pin 11 is connected to ground.

Pin 12 of AN7223 is connected to +6Volts through a 5.5MHz IFT coil. A resistor R1 (2K2) is connected between a 5.5MHz IFT coil. Pin 14 of AN 7223 is connected to +6Volts.

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 Pins 16,17 are also connected to ground through an electrolytic capacitors C6(22uF/25V), C7 (10uF/25V). A capacitor C6 is connected between ground and pin 17.

An audio output is taken out from pin 13 of AN 7223 through an electrolytic capacitor C13 (10uF/25V) from a 2-pin connector.

Resistor R2 (470K) is connected between a base of Q1 (BF494) and +6Volts. Resistor R (470) is connected between ground and emitter of Q1 (BF494). Coil L1 is connected in parallel with a VC1 (2-22pF) and connected to + 6Volts and collector of Q1 (BF494). Capacitor C11 (10pF) is connected between an emitter and collector of Q1.Capacitor C10 (.01uF) is connected between base and ground.

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Fig. 2: Author’s Prototype

Construction and Calibration

Capacitor C12(33pF) is connected between an emitter of Q1 and to an input terminal of a 5.5MHz ceramic filter and to a pin 1 of IC1 (AN7223). An antenna of 75cm long wire is connected to a base of Q1 (BF494) through a capacitor C9(102).

After inserting all the components take a 25W soldering iron and solder all the components. Don’t insert an IC on a IC socket while soldering IC socket on  zero PCB.Before we construct this radio we will make a coil L1 of 5 turns of 23 SWG wire on a 5mm air core.

Take a piece of 23 SWG wire and remove its enamel on two ends. Now take a 5mm drill bit and gently wound 5 turns of 23 SWG copper wires.

Now take a 18-pin IC socket and place it on a middle of a board. You may also use a zero PCB (5cm*7cm).

Place a transistor Q1 on a left side of a zeroboard and 2-pin connector to a right side of a zero board.

Take a 5.5 MHz IFT coil and connect it in parallel with a resistor R1 (2K2).Now connect them to a pin 12 of IC1 and +6 Volts.

For a calibration you will need a low power Audio amplifier. Here i used a LM 386 AF amplifier.

Connect a speaker and connect it an AF amplifier. Also connect a +6 Volts to an AF amplifier.

Now connect an output (2-pin connector) from your FM radio to an input of AF amplifier.

Connect 4* 1.5V AA battery or 6 Volts battery to your FM radio receiver. You will hear a hissing sound comming out from a speaker of an Audio amplifier.

Gently tune a VC1 trimmer capacitor or adjust a coil L1 by pulling towards. You will hear many stations.

Adjust a core of 5.5MHz IFT coil until you hear a clear station coming out from your FM radio.So, your FM radio is working and ready for listening.


Q1: BF494
IC1: AN7223
R1: 2K2
R3: 470
C1: 100uF/25V
C3, C4:203
C5: 223
C6: 22uF/25V
X1:2-pin 5.5MHz Ceramic filter
T1: 5.5 MHz IFT coil
VC1: 2-22pF Trimmer
2-pins connector
8-pin IC socket
5cm*7cm Zero PCB


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