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pocket fm receiver circuit diagram

Simple FM Receiver Circuit

This is the most simple fm receiver with good performances that works great even if the sensitivity is not too high. The working principle of this radio receiver may seem a little unusual. It is made of an oscillator (T2 and T3) that is synchronized with the received frequency of T1 which works as a broadband preamplifier in VHF range.

How does the fm receiver works

The oscillator is adjusted between 87 … 108 MHz with C5. Because of the synchronization, the oscillator output will have the same frequency deviation as the received signal from the fm antenna. This deviations are caused by the broadcasted audio information. The frequency modulated signal show up on P1 + R5. Low pass filter R6/C6 extracts the audio signal and then is amplifier by T4 … T6 and transmitted at the output through C9 capacitor.

FM Receiver Circuit Schematic

small fm receiver circuit schematic

The coil details are presented in the fm receiver circuit diagram. The radio receiver is adjusted on different stations with the help of C5. P1 potentiometer is adjusted untill the best reception is obtained. If we attach an audio amplifier and a speaker then this frequency modulated receiver can be made very compact as a pocket radio.

127 Comments

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  • Name *frank

    can you pls tell me the exact codes of c 4.7nf and 680n .email me pls

  • Yusuf muhammad

    that is very good circuit , Thanx to u sir.

  • yazar

    please can i get an article on the circuit diagram of a fm radio reciever that dose not make use of an integrated circuit.

  • Aurel

    Gene..
    It looks that you talk about original circuit explained
    in topic post..right?
    Well ..some people say that original circuit with BF324
    work great…but because i dont have this transistors i cannot
    confirm that work.
    I have tried with BF506 but without any result.

  • Gene

    I believe there is an error in the shcematic. I tend to think that the RF should be injected to the hot end of the resonant circuit and not at the emitters of the oscillator. The AF is available at the emitters, as shown. The RF amp stage is not very good. It actually may be better to omit it and connect the antenna directly to the hot end of the resonant.

    The oscillator works well. I use it as a VCO having substituted the capacitor with a varactor diode. The emitter trimmer I use is 22k with a series resistor as low as 2k2. It delivers several tens of mVs. It is fairly stable and provides reasonably good sinewave. I think detection is achieved by sensing the current consuption of the oscillator. When incoming signal deviates from resonance the oscillator tries to “fight back” by taking more current.

  • Aurel

    you can use almost any RF transistor for VHF like
    N9018
    BFR91A
    C3355

    I use in my circuit pnp type BF970 so don’t forget
    that you need for my circuit pnp and not npn
    type like is bf199..ok!

  • sachin

    could not find bf 199 transistor.would u plz name some of its equivalents

  • Aurel

    Anyone build my version of PNP FM super regen receiver?

  • Aurel

    You not have nF capacitors ???
    But which one ? one from original schematic,
    or c2,c4 (5nF) from circuit presented by me?

    http://rubendev.888webhost.com/forum/

    • ym

      I just want to know, if I will place combination ( series parallel )of capacitor instead of a equivalent particular one, then will it affect my circuit performance?

  • ym

    i m not having nF capacitor , what can i do instead please reply me this is my miniproject.

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