Simple FM receiver on a chip

You will need just one chip to build a simple and complete FM receiver that is capable of receiving radio stations in the range of 75-120 MHz. The FM receiver contains a minimum of parts, and its configuration, after assembly, is reduced to a minimum. It also has good sensitivity for receiving VHF FM radio stations.
All this thanks to the Philips TDA7000 microcircuit, which can be bought without problems on our favorite Ali Express - link.

Receiver circuit

Here is the receiver circuit itself. Two more microcircuits were added to it, so that in the end it turned out to be a completely finished device. Let's start looking at the diagram from right to left. The now classic low-frequency amplifier for a small dynamic head is assembled using the LM386 chip. Here, I think, everything is clear. A variable resistor adjusts the volume of the receiver. Next, a 7805 stabilizer is added above, which converts and stabilizes the supply voltage to 5 V. Which is needed to power the microcircuit of the receiver itself. And finally, the receiver itself is built on the TDA7000. Both coils contain 4.5 turns of PEV-2 0.5 wire with a winding diameter of 5 mm.The second coil is wound on a frame with a ferrite trimmer. The receiver is tuned to the frequency using a variable resistor. The voltage from which goes to the varicap, which in turn changes its capacitance.
If desired, varicap and electronic control can be abandoned. And the frequency can be tuned either with a tuning core or with a variable capacitor.

FM Receiver Board

I drew the circuit board for the receiver in such a way as not to drill holes in it, but to solder everything from the top, as with SMD components.

Placing elements on the board

Used classic LUT technology to produce the board.


I printed it, heated it with an iron, etched it and washed off the toner.


Soldered all the elements.

Receiver setup

After turning it on, if everything is assembled correctly, you should hear hissing in the dynamic head. This means that everything is working fine for now. The whole setup comes down to setting up the circuit and selecting the range for reception. I make adjustments by rotating the coil core. Once the reception range is configured, channels in it can be searched for using a variable resistor.

Conclusion

The microcircuit has good sensitivity, and a half-meter piece of wire, instead of an antenna, can pick up a large number of radio stations. The sound is clear, without distortion. This circuit can be used in a simple radio station, instead of a receiver on a supergenerative detector.

Watch the video of work

source