The assembly is carried out according to a classic receiver scheme with reaction (regenerative).
It consists of two floors, one for radio frequency, equipped with T1 and the second for audio frequency, equipped with T2.
The radio frequency floor works as follows:
The signal of the broadcasting station is selected by the circuit formed by L2 - C2 and then it is amplified by the transistor T1. Part of the amplified radio frequency signal is returned to the input circuit, by means of capacitor C3. In this way, a substantial strengthening of the signal from a certain radio station is created.
By means of potentiometer R1, the reaction of the circuit is dosed, up to the threshold of the circuit entering oscillation. When the assembly begins to oscillate, sharp sounds and whistles are heard.
The detection of the useful signal (audio) is also carried out on this floor, equipped with the T1 transistor.
The obtained audio signal is applied to the audio frequency stage equipped with the T2 transistor.