One Transistor FM Radio Receiver Circuit schematic

Here’s simple FM receiver circuit for a simple superregenerative FM radio. It is sensitive, selective, and has enough audio drive for an earphone. These designs generally have low component counts, however the design or my construction have been far from simple.

FM Receiver Schematic

FM Radio Receiver Circuit Layout
Because this is a superregenerative design, component layout can be very important. The tuning capacitor, C3, has three leads. Only the outer two leads are used; the middle lead of C3 is not connected. Arrange L1 fairly close to C3, but keep it away from where your hand will be. If your hand is too close to L1 while you tune the radio, it will make tuning very difficult.
Winding L1
L1 sets the frequency of the radio, acts as the antenna, and is the primary adjustment for super-regeneration. Although it has many important jobs, it is easy to construct. Get any cylindrical object that is just under 1/2 inch (13 mm) in diameter. I used a thick pencil from my son’s grade school class, but a magic marker or large drill bit work just fine. #20 bare solid wire works the best, but any wire that holds its shape will do. Wind 6 turns tightly, side-by-side, on the cylinder, then slip the wire off. Spread the windings apart from each other so the whole coil is just under an inch (2.5 cm) long. Find the midpoint and solder a small wire for C2 there. Mount the ends of the wire on your circuit board keeping some clearance between the coil and the circuit board.
A tuning knob for C3
C3 does not come with a knob and I have not found a source. A knob is important to keep your hand away from the capacitor and coil when you tune in stations. The solution is to use a #4 nylon screw. Twist the nylon screw into the threads of the C3 tuning handle. The #4 screw is the wrong thread pitch and will jam (bind) in the threads. This is what you want to happen. Tighten the screw just enough so it stays put as you tune thecapacitor. The resulting arrangement works quite well.
FM Radio Receiver Circuit Adjustment
If the radio is wired correctly, there are three possible things you can hear when you turn it on: 1) a radio station, 2) a rushing noise, 3) a squeal, and 4) nothing. If you got a radio station, you are in good shape. Use another FM radio to see where you are on the FM band. You can change the tuning range of C3 by squeezing L1 or change C1. If you hear arushing noise, you will probably be able to tune in a station.
Try the tuning control and see what you get. If you hear a squeal or hear nothing, then the circuit is oscillating too little or too much. Try spreading or compressing L1. Double check your connections. If you don’t make any progress, then you need to change R4. Replace R4 with a 20K or larger potentiometer (up to 50K). A trimmer potentiometer is best. Adjust R4 until you can reliably tune in stations. Once the circuit is working, you can remove the potentiometer, measure its value, and replace it with a fixed resistor. Some people might want to build the set from the start with a trimmer potentiometer in place (e.g., Mouser 569-72PM-25K).
Browse : FM Receiver on Amazon
See more: MP3 FM Transistor

Source: Build A One Transistor FM Radio

latest CXA1019 FM Receiver Schematic

Receiver Schematic is an FM receiver built with a single IC FM / AM CXA1019, designed specifically for radio-cassette tape recorders and headphone tape recorders.

CXA1019 FM Receiver Schematic

CXA1019 FM receiver schematic is quite easy to build because it uses a small number of components with low current consumption is 5.3 mA at 3V Vcc. However, it’s an AF amplifier with large output of about 500mW at 8? load impedance.

CXA1019 FM Receiver-PCB Top

PCB Dimension : width=7.95 cm, Height=4.90 cm

CXA1019 FM Receiver-PCB Bottom

CXA1019 FM Receiver Part List

CXA1019 FM Receiver Part List

XCA1019 FM Receiver Parts

One Transistor FM Radio Receiver Circuit

Here’s simple FM receiver circuit for a simple superregenerative FM radio. It is sensitive, selective, and has enough audio drive for an earphone. These designs generally have low component counts, however the design or my construction have been far from simple.

FM Receiver Schematic

FM Radio Receiver Circuit Layout
Because this is a superregenerative design, component layout can be very important. The tuning capacitor, C3, has three leads. Only the outer two leads are used; the middle lead of C3 is not connected. Arrange L1 fairly close to C3, but keep it away from where your hand will be. If your hand is too close to L1 while you tune the radio, it will make tuning very difficult.

Winding L1
L1 sets the frequency of the radio, acts as the antenna, and is the primary adjustment for super-regeneration. Although it has many important jobs, it is easy to construct. Get any cylindrical object that is just under 1/2 inch (13 mm) in diameter. I used a thick pencil from my son’s grade school class, but a magic marker or large drill bit work just fine. #20 bare solid wire works the best, but any wire that holds its shape will do. Wind 6 turns tightly, side-by-side, on the cylinder, then slip the wire off. Spread the windings apart from each other so the whole coil is just under an inch (2.5 cm) long. Find the midpoint and solder a small wire for C2 there. Mount the ends of the wire on your circuit board keeping some clearance between the coil and the circuit board.

A tuning knob for C3

C3 does not come with a knob and I have not found a source. A knob is important to keep your hand away from the capacitor and coil when you tune in stations. The solution is to use a #4 nylon screw. Twist the nylon screw into the threads of the C3 tuning handle. The #4 screw is the wrong thread pitch and will jam (bind) in the threads. This is what you want to happen. Tighten the screw just enough so it stays put as you tune the capacitor. The resulting arrangement works quite well.

FM Radio Receiver Circuit Adjustment
If the radio is wired correctly, there are three possible things you can hear when you turn it on: 1) a radio station, 2) a rushing noise, 3) a squeal, and 4) nothing. If you got a radio station, you are in good shape. Use another FM radio to see where you are on the FM band. You can change the tuning range of C3 by squeezing L1 or change C1. If you hear a rushing noise, you will probably be able to tune in a station.

Try the tuning control and see what you get. If you hear a squeal or hear nothing, then the circuit is oscillating too little or too much. Try spreading or compressing L1. Double check your connections. If you don’t make any progress, then you need to change R4. Replace R4 with a 20K or larger potentiometer (up to 50K). A trimmer potentiometer is best. Adjust R4 until you can reliably tune in stations. Once the circuit is working, you can remove the potentiometer, measure its value, and replace it with a fixed resistor. Some people might want to build the set from the start with a trimmer potentiometer in place (e.g., Mouser 569-72PM-25K).

Browse : FM Receiver on Amazon

See more: MP3 FM Transistor

Source: Build A One Transistor FM Radio

Circuit Diagram FM Antenna Booster

FM Antenna Booster Circuit Diagram

This is a low cost fm antenna booster that can be used to listen to programmes from distant FM stations clearly. The antenna fm booster circuit comprises a common-emitter tuned RF preamplifier wired around VHF/UHF transistor 2SC2570 (C2570).

Assemble the circuit on a good-quality PCB (preferably, glass-epoxy). Adjust input/output trimmers (VC1/VC2) for maximum gain.

Input coil L1 consists of four turns of 20SWG enamelled copper wire (slightly space wound) over 5mm diameter former. It is tapped at the first turn from ground lead side. Coil L2 is similar to L1, but has only three turns. Pin configuration of transistor 2SC2570 is shown in the fm antenna booster schematic.

One Transistor FM Radio Receiver Circuit

One Transistor FM Radio Receiver Circuit
Here’s simple FM receiver circuit for a simple superregenerative FM radio. It is sensitive, selective, and has enough audio drive for an earphone. These designs generally have low component counts, however the design or my construction have been far from simple.

FM Receiver Schematic

FM Radio Receiver Circuit Layout
Because this is a superregenerative design, component layout can be very important. The tuning capacitor, C3, has three leads. Only the outer two leads are used; the middle lead of C3 is not connected. Arrange L1 fairly close to C3, but keep it away from where your hand will be. If your hand is too close to L1 while you tune the radio, it will make tuning very difficult.
Winding L1
L1 sets the frequency of the radio, acts as the antenna, and is the primary adjustment for super-regeneration. Although it has many important jobs, it is easy to construct. Get any cylindrical object that is just under 1/2 inch (13 mm) in diameter. I used a thick pencil from my son’s grade school class, but a magic marker or large drill bit work just fine. #20 bare solid wire works the best, but any wire that holds its shape will do. Wind 6 turns tightly, side-by-side, on the cylinder, then slip the wire off. Spread the windings apart from each other so the whole coil is just under an inch (2.5 cm) long. Find the midpoint and solder a small wire for C2 there. Mount the ends of the wire on your circuit board keeping some clearance between the coil and the circuit board.
A tuning knob for C3
C3 does not come with a knob and I have not found a source. A knob is important to keep your hand away from the capacitor and coil when you tune in stations. The solution is to use a #4 nylon screw. Twist the nylon screw into the threads of the C3 tuning handle. The #4 screw is the wrong thread pitch and will jam (bind) in the threads. This is what you want to happen. Tighten the screw just enough so it stays put as you tune thecapacitor. The resulting arrangement works quite well.
FM Radio Receiver Circuit Adjustment
If the radio is wired correctly, there are three possible things you can hear when you turn it on: 1) a radio station, 2) a rushing noise, 3) a squeal, and 4) nothing. If you got a radio station, you are in good shape. Use another FM radio to see where you are on the FM band. You can change the tuning range of C3 by squeezing L1 or change C1. If you hear a rushing noise, you will probably be able to tune in a station.
Try the tuning control and see what you get. If you hear a squeal or hear nothing, then the circuit is oscillating too little or too much. Try spreading or compressing L1. Double check your connections. If you don’t make any progress, then you need to change R4. Replace R4 with a 20K or larger potentiometer (up to 50K). A trimmer potentiometer is best. Adjust R4 until you can reliably tune in stations. Oncethe circuit is working, you can remove the potentiometer, measure its value, and replace it with a fixed resistor. Some people might want to build the set from the start with a trimmer potentiometer in place (e.g., Mouser 569-72PM-25K).
Browse : FM Receiver on Amazon
See more: MP3 FM Transistor

Source: Build A One Transistor FM Radio

VHF FM Receiver TDA7000 88-108 MHz

Here is a very simple VHF FM receiver which is little more than a single IC and a "slack handfull" of capacitors. Note that an external amplifier is a really necessity since the unit only delivers about 70mV of AF.
See High Power FM Wireless Microphone transmitters, probably because it is so simple too.

The 10K resistor (*) is only required if you want the receiver to mute (squelch) under no-signal conditions. You could add a 100K in series with this resistor to get an adjustable squelch. This circuit will JUST drive a crystal earphone or high impedance headphones directly, but an output isolating capacitor (100nF) is needed for any other device. L1 is 6 turns No 18 SWG enamelled wire on a 5mm former, but you may have to play with the values a bit. I used a coil fabricated on the PCB itself, tuned with a trimmer capacitor.

All the other components are just a bunch of capacitors which are fitted to the board at the other side of the chip, just to make it look a bit prettier.

As you can see, this receiver is VERY sensitive, small and seems to work very well indeed. It is in fact a full superhet receiver with a very low RC tuned IF. The Image signal is rejected by the action of the AFC which functions to push it away. With suitable antennas and terrain, with this receiver you could easily get the full 500 meters from the FM wireless microphone v5. I am offering this receiver in kit form, including solder, antenna wire etc. All you will need to provide is the battery, tools and soldering iron. Here is the kit version fully assembled.

The total size is 45mm x 48mm. If there is any interest in the kit then I may even add an AF amplifier kit so that you can make a full bedside/table radio.

Source: TDA7000 RX