This simple AM transmitter circuit include of many parts. There is a transistor Q1 act as increase the audio signal (AF) from the crystal microphone and a resistors-R3 that limit amplitude of sound signal is increased by Q1
The transistor – Q2 generate a radio frequencies (RF) in form of the colpitts oscillator circuit. The inductance – L1 and both capacitor C4 and C5 are used to set the a radio frequencies (RF) output.
The audio signal of Q1 is sent to Q2. It make the amplitude of the RF from Q2 change to by the height of the sound signal. In the final, the RF signal which has the height of the peak height – low as well as the sound signal will be Sent radiating broadcast antenna.
The frequency broadcast transmitter can be adjusted by tuning the capacitance of C4. The frequency of the transmitter in the broadcast system AM range. Which listen to a radio broadcast in AM General. and this AM transmitter can be spread out over a distance of several hundred feet long.