Saturday, May 25, 2024

Designing Simple FM Radio Receiver Circuit

A radio or FM receiver is an electronic device that receives radio waves and converts the information carried by them to a usable form. An antenna is used to catch the desired frequency waves.

The receiver uses electronic filters to separate the desired signal from all the other signals picked up by the antenna, an electronic amplifier to increase the power of the signal for further processing, and finally recovers the desired information through demodulation.

Of the radio waves, FM is the most popular one. Frequency modulation is widely used for FM radio broadcasting. It is also used in telemetry, radar, seismic prospecting, and monitoring newborns for seizures via EEG, two-way radio communication systems, music synthesis, magnetic tape-recording systems, and some video-transmission systems.

An advantage of frequency modulation is that it has a larger signal-to-noise ratio and therefore rejects radio frequency interference better than an equal power amplitude modulation (AM) signal.

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We have also designed a simple stereo amplifier circuit.

FM Frequency Ranges

Frequency modulation is used in a radio broadcast in the 88-108MHz VHF frequency band. This bandwidth range is marked as FM on the band scales of radio receivers, and the devices that are able to receive such signals are called FM receivers.

The FM radio transmitter has a 200kHz wide channel. The maximum audio frequency transmitted in FM is 15 kHz as compared to 4.5 kHz in AM. This allows a much larger range of frequencies to be transferred in FM and thus the quality of FM transmission is significantly higher than that of AM transmission.

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Presented below is an FM Radio Circuit Diagram along with its full explanation.

FM Receiver Circuit – Components

  • IC- LM386
  • T1 BF494
  • T2 BF495
  • 4 turn 22SWG 4mm dia air core
  • C1 220nF
  • C2 2.2nF
  • C 100nF * 2
  • C4 10uF
  • C5 10uF (25 V)
  • C7 47nF
  • C8 220 uF(25 V)
  • C9 100 uF (25 V) * 2
  • R 10KΩ * 2
  • R3 1KΩ
  • R4 10Ω
  • Variable resistance
  • Variable capacitance
  • Speaker
  • Switch
  • Antenna
  • Battery

FM Receiver Circuit Explanation

Here’s a simple FM receiver circuit with minimum components for local FM reception. Transistor BF495 (T2), together with a 10k resistor (R1), coil L, 22pF variable capacitor (VC), and internal capacitances of transistor BF494 (T1), comprises the Colpitts oscillator.

Trimmer VC sets the resonance frequency of this oscillator to the frequency of the transmitting station that we wish to listen to. That is, it has to be tuned between 88 and 108 MHz.

The information signal used in the transmitter to perform the modulation is extracted on resistor R1 and fed to the audio amplifier over a 220nF coupling capacitor (C1).

FM Receiver Circuit Diagram
Fig.1: FM Receiver Circuit Diagram

You should be able to change the capacitance of the variable capacitor from a couple of picofarads to about 20 pF. So, a 22pF trimmer is a good choice to be used as VC in the circuit. It is readily available in the market.

If you are using some other capacitor that has a larger capacitance and are unable to receive the full FM bandwidth (88-108 MHz), try changing the value of VC. Its capacitance is to be determined experimentally.

The self-supporting coil L has four turns of 22 SWG enamelled copper wire, with the air core having a 4mm internal diameter. It can be constructed on any cylindrical object, such as a pencil or pen, having a diameter of 4 mm.

When the required number of turns of the coil has reached, the coil is taken off the cylinder and stretched a little so that the turns don’t touch each other.

Capacitors C3 (100nF) and C10 (100µF, 25V), together with R3 (1k), comprise a band-pass filter for very low frequencies, which is used to separate the low-frequency signal from the high-frequency signal in the receiver.

Also Check: long-range FM transmitter

Antenna is a Bit Tricky…

You can use the telescopic antenna of any unused device. However, A good reception can also be obtained with a piece of isolated copper wire about 60 cm long. The optimum length of copper wire can be found experimentally.

You can also Read: Different Types of Antennas

The performance of this tiny receiver depends on several factors such as quality and turns of coil L, aerial type, and distance from the FM transmitter.

IC LM386 is an audio power amplifier designed for use in low-voltage consumer applications. It provides 1 to 2 watts, which is enough to drive any small-size speaker. The 22k volume control (VR) is a logarithmic potentiometer that is connected to pin 3 and the amplified output is obtained at pin 5 of IC LM386. The receiver can be operated off a 6V-9V battery.

This circuit costs around ₹120.

More on FM receivers in the slideshow below.

Chapter 5: FM Receivers from mkazree

You can also check the interesting DIY electronics projects.

This article was published in June 2003 and recently updated on August 2023.


  1. if i use a mp3 song from my smartphone as my message signal to the transmitter and if transmit it , can i use this circuit to reciever , like can i tune this circuit to the transmitter frequency

    • Please note that if you are near a commercial FM broadcast station, you can receive the FM channel signals in this circuit. Otherwise, you won’t receive the commercial broadcast signal. This is because it is a simple circuit and does not have the power and sensitivity to receive the weak signal.
      However, you can construct any FM transmitter circuit which works in the FM band 88-108 MHz and
      receive the transmitted signal using this simple FM receiver circuit.

    • I agree – this circuit does not work. The RC Low Pass filter to the 22k pot is doing its job (sort of). The cut-off needs to be sharper (around 7kHz at -3dB). There is also no envelope detection FM to AM conversion so not sure how audio is achieved at the speaker. See slides at bottom of this article for FM detection.

  2. This is very easy and Sensitive circuit. But when i tested it did not work. this circuit is able searchable Radio Frequency but no Get any Signal of any Station. What may be problem ?? When i remove the 10K resistor after 220n capacitor and connect direct the output then i get even noise output. But with 10K resistor nothing get any output.

  3. Reception of weak signals can be improved by connecting an outdoor yagi antenna in the case of TVs. But for FM radios, simply connecting a long outdoor wire to the telescopic antenna does not improve; on the other hand worsens, perhaps due to shift of resonance frequency or something. There is no radio having coaxial antenna socket. Can it be possible to fix a coaxial outdoor antenna input socket to a simple FM radio for inserting an antenna balun to make reception as good as TVs ? Pl suggest any other means to improve reception.

  4. Correct me if I am wrong… The frequency range of BF494-495 is somewhere at 200MHz. The transistors could be replaced provided that the input frequency will not somewhat exceed the frequency range the consequences is rather a mumble output. The BC547 which was used also in the transmitter circuit was used to replace BF494 and 495.

  5. How about one with tubes? Yes long gone but they are still around and work! The one with the ECC85 and other tubes. How do you play with the range it works without experiments, how do you tune it etc. it is much more didactic to try than with transistors only, inspite of the HV. Tks.

  6. The circuit was designed and tested with transistor only. Tubes are not easily available in the market.
    Tuning is done using trimmer(VC) and volume control with 22k potentiometer as given in the circuit.

  7. I’ve completed this project on a protoboard and it doesn’t seem to work. Connections have been thoroughly checked in comparison to the schematic above. Everything was done as shown on the schematic with the exception of the transistors and inductor. For both transistors, the 2N3707 was used which is equivalent to the BF494. The 2N3707 was used in place of the BF495 because in a previous question you stated a BF494 will work in place of a BF495. The inductor is a 24AWG Enameled copper wire consisting of 12 loops, each being 4mm in diameter. Even after adjusting the potentiometer and variable capacitor in various positions, no sound is emitted from the eight-ohm speaker.

    Also, I noticed quite a few questions unanswered on this thread that could potentially provide people with solutions;
    SB’s Question
    “I have tried to build the project but it didn’t work out, and it doesn’t compare with the datasheet of the LM 386. Why is the Vs via C6 going to the ground?”

    Arne’s Question
    “I just looked up the data sheet for the BF494 at Philips, and noted that the Collector and Base in your diagram seem swapped. Are you aware of that?”

    Not sure whether this is a problem on my side or yours, but a lot of people seem to be complaining about the radio not working. I’m sure you got your’s working so there may likely be a translation error between your actual project and the information posted on this page. Maybe we can exchange images of our finished projects and figure out what the problem is. Just like anyone else, it makes me angry to put money and time into something that should work, but doesn’t. Thanks in advance.

  8. Built this and does not work, the LM368 amp works fine, but the tuning coil with capacitor do not pick up RF.
    Something is wrong here, i built it on a perf board with short soldering distances and it does not pick up anything, even a programmable Arduino transmitter is not picked up while my boafeng pick up the transmitter without any issues.

  9. Can someone please answer the question that has been posed many times, and help all of us that are eager to learn and understand? Where is the signal extraction occurring? Is the incoming RF affecting the base/collector capacitance thus affecting the frequency of the oscillator, then relying on slope detection (frequency response of the LC circuit in the collector leg), or, is this circuit relying on the nonlinearity of the base/emitter junction causing the mixing (multiplying) of the incoming RF and the oscillator signals and causing an intermediate frequency?

  10. This would work better as an AM receiver. There is no FM detection circuit. Needs an RF choke at the battery +ve terminal. The bandpass filter is not required. These are just smoothing capacitors (C3, C6, C9, C10) to take the ripple off Vs (pin 6) of LM386. AGAIN – there is no FM detection or FM-AM conversion, so don’t see how this will produce audio. During testing, I fed FM (100MHz) signal directly from AWG with 1KHz mod frequency 2khz freq deviation. Could see the attenuated carrier and the modulated frequency at PIN 3 of LM386. Output did show modulated frequency but still with freq deviation rather than amplitude modulation.


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