A simple FM receiver on a chip
Just one chip is needed for you to build a simple and high-grade FM receiver that can receive radio stations in the range of 75-120 MHz. FM receiver contains a minimum of parts, and its setting, after assembly, is minimized. It also has a good sensitivity for receiving FM VHF radio stations. All this thanks to Philips chip TDA7000, which can be bought without problems on our favorite Ali Express -link.Here is the receiver circuit itself. Two more microcircuits are added to it in order to get a fully finished device at the end. We begin to consider the scheme from right to left. On the LM386 chassis, the low-frequency amplifier for a small dynamic head, which has already become a classic, is assembled. Here, I think everything is clear. The variable resistor adjusts the receiver volume. Further, a stabilizer 7805 has been added above, which converts and stabilizes the supply voltage up to 5 V.Which is needed to power the microcircuit of the receiver itself. Finally, the receiver itself is assembled on the TDA7000. Both coils contain 4.5 turns of the wire sew-2 0.5 with a winding diameter of 5 mm. The second coil is wound onto a frame with a ferrite trimmer. The receiver is tuned to the frequency by a variable resistor. The voltage from which goes to the varicap, which in turn changes its capacity. If desired, from the varicap and electronic control can be discarded. And the frequency can be adjusted either with a trimmer core or with a variable capacitor.I used classical LUT technology to produce a board.Printed, warmed up with an iron, etched and washed away the toner.Soldered all the elements.
FM receiver cardI drew the circuit board for the receiver so as not to check the holes in it, but rather like with SMD components solder all from the top.
Placing elements on the board
Receiver SetupAfter turning on, if everything is assembled correctly, you should hear a hiss in the dynamic head. This means that everything is working fine so far. All settings are reduced to setting the contour and select the band to receive. oiku rotating the coil core. As the reception range is tuned, the channels in it can be searched for with a variable resistor.
ConclusionThe microcircuit has good sensitivity, and you can catch a large number of radio stations instead of an antenna for a half-meter wire. The sound is clear, without distortion. Such a scheme can be applied in a simple radio station, instead of a receiver on a supergenerative detector.
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