Home » Assorted Circuits » Single Transistor Radio Receiver Circuit

Have a Question?

Please feel free to ask any circuit related question and get a quick solution from me.

Single Transistor Radio Receiver Circuit

This is probably the simplest radio that one could ever
imagine of making. The circuit is so simple that it could be finished
assembling within a few minutes and you are already listening your favorite
programs over it.

What are the fundamental criteria associated with radio
reception? An antenna stage, a band selector stage, a demodulator stage and a
receiving element.
When all of these come together radio reception becomes as
simple as a piece of cake.
The circuit of a single transistor radio shown here though
looks pretty ordinary, incorporates all the above stages and thus becomes just
suitable for receiving the radio stations.
However simplicity will always involve some drawbacks also,
here the present design will be capable of receiving only strong stations and
also selectivity might not be very pleasing, typically if there are a couple of
strong stations mingling around the band.
The figure below shows how the single transistor radio can
be made, we can clearly see that it just involves a single transistor as the main
active component.
A regular type of MW antenna coil has been used for
collecting or sensing the MW receptions.
The coil is tuned using a GANG condenser or a variable
capacitor which is connected in parallel to the antenna coil.
The coil and the GANG together form a resonant tank circuit,
which lock on to the received or the resonant frequency at a particular
setting.
The concentrated but very low in power signal from the above
LC tuned stage is fed to the base of the transistor which as performs the function
of a demodulator as well as a amplifier stage.
The coupling capacitor at the base of the transistor makes
sure only the radio information passes to the transistor while the DC component
from the supply is appropriately blocked.
A 64 Ohm headphone becomes the collector load of the
transistor, where the demodulated and amplified signal is applied.
When connected, the received signals can be distinctly heard
oer the headphones with this little “audio marvel”
Plugging in the headphone initiates the circuit and the
circuit starts operating with its functions and the switches OFF itself when
the headphone is removed from the circuit. This eliminates the need of an
external switch to be associated with the circuit, making the unit very
compact.
Single Transistor Radio Receiver Circuit
The circuit requires just 1.5 V for operating which can be
implemented using a single button type of cell.

You would also want to build this ONE TRANSISTOR FM RADIO CIRCUIT


36 Comments

  1. you told that any parties in Mumbai can hire you for project. I am from Karnataka, Dharwad. I am studying in kendriya vidyala dharwad ,7th standard. I am really interested in electronics.will you help me while making my projects? I tried 4 radio receiver circuits, in fact they failed. Are you sure this circuit will work?

    • Okay, thank you for your informations!
      – but I still have one another question about your circuit:
      What do you think – how is the quality of the received sound, if I build a FM receiver just some meters next to the receiver? – do you think, the sound will be good or have you any other idea, how I could realise this?
      I'm asking, because I want to make a pair of headphones wireless – but with power consumption as low as possible.

      Thank you in advance, Mr. Majumdar!

    • Please excuse me, I actually wanted to ask you, how good the quality of your published receiver is?
      I wanted to ask you that question, because I intend to build your fm receiver and a fm transmitter.
      From last one (transmitter), I want to transmit an audio signal to a pair of headphones, which I want to make wireless due to your receiver circuit?
      You know what I mean? – Basicly I just wanted to know, what you think about this idea and if the quality is good enough.

    • sorry but you should put the question under the relevant article, because i have so many transmitter related articles, can't really figure out which circuit you are referring to.

      anyway all my circuits are correct and will surely work if done correctly.

  2. Good day sir

    Will this capture FM signals?

    I used BF199-based replacement Transistor istead of BC547. and used Standard FM Tunning Gang CAP paralleled to Standard MW AM antenna coil.

    Will this work?

  3. in this circuit it could be for 3 reasons:

    to stabilize the 1.5V when a strong reception is detected,

    to ground unwanted high frequency response and to make the audio clearer.

    to safeguard te transistor from earphone coil back emfs…

  4. Hi, I have made this circuit but it is unable to catch any FM signals (I just need to catch 1 channel).
    can you tell me coil's specifications (thickness, diameter and turns) ?

Leave a comment

Your email address will not be published. Required fields are marked *

Archives