Building an AM radio yourself is not a difficult task. With some basic engineering, you can create your own simple AM radio receiver at home. Connecting the components creates a functional AM circuit, which you can use for broadcasting. Keep in mind; this method will work to tune into stations nearby and not too far away from your location.
Amplitude Modulation (AM) or the medium-wave band operates by transmitting signals over the air. The receiver then picks these signals, modulates them, and outputs them as a copy of the original audio. It performs this job by employing a few basic components, such as capacitors, transistors, resistors, batteries, and a speaker. You will need these components to make an AM radio.
This article is a complete guide on how one can make an AM radio circuit from scratch. Let’s start!
Materials Needed to Build an AM Radio
To begin, you must first gather the components. You can find easily find these at electronic and hardware stores. Many of the parts are also available online.
|Fast Recovery Diodes (1N4148)||2|
|Female headers (25 pins)||1|
|Female headers (24 pins)-for soldering||1|
|AA battery slot||1|
|AA NiMH/Alkaline battery||2|
|5-pin male headers||1|
|Variable capacitor 1-55 pF||1|
|DIY RF inductor/AM coil||1|
|Nano Farad ceramic capacitor (104, 103)||1|
|Carbon film resistor (3K9, 2K2, 1M, 4K7)||1|
|Stereo female audio jack||1|
Besides these, you will also need some tools, such as
- Soldering iron (and solder)
- Soldering flux
- Helping hand for soldering
- 3-color breadboard wire
- Plastic head screwdriver
How to make an AM radio receiver- Steps
The first and most important step to making an AM radio is learning how to do the AM coil or RF inductor. What you need is a cylinder or planar ferrite core, having an internal diameter of 0.8 cm. Next, you will need an enameled copper wire (30 AWG) to wound to the ferrite core (60 windings). You may use glue or tape to keep the windings in place. Measure its continuity to make sure that you have formed the AM coil properly. This inductor gets efficient functioning at your desired frequency, ranging from 550 to 1500 kHz.
Having a clear picture of the end product as a diagram is crucial. It helps you know where each part needs to be placed and eventually soldered. Moreover, it helps prevent any mistakes that may cause problems later on. You can find several sample circuit diagrams of a simple AM radio circuit to follow while making your own radio. To explain it simply, the variable capacitor and AM coil work together to make a tank circuit. This circuit picks signals from the antenna, which are detected by the diode. The signal passes to the transistor, which amplifies the modulated signal and demodulates it. The audio is then output via a speaker or headphones.
The Nano Farad ceramic capacitor and second transistor help in picking the purest audio signals. You may also attach a base biased circuit next to the tank circuit.
Solder the parts
Now that you’re familiar with the layout of the circuit, the next step is to solder the components and make connections using male/female headers. Connect the diode’s positive anode to the female header’s first pin. Next, connect and solder the next positive anode of the second diode to the first diode. Similarly, move ahead by soldering the cathode of the second diode to the female header’s second pin.
Additionally, you will need to solder the Nano Farad capacitor to the 3rd and 4th pins of the female header. Next, you will need to connect the 2K2 resistor to the capacitor, with the trimmer capacitor between the 6th female header pin and the 2K2 resistor.
Solder the transistors (NPN) adjacent to the trimmer. You will also need to create a bridge between the 2nd transistor and potentiometer’s first pin, and another between the potentiometer’s second and third pins. Next, solder the Nano Farad capacitor to the bridge and the resistor between the transistor and collector according to the circuit diagram you’re following.
Attach the positive and negative rails
First, connect the red-colored wire to a 1v6 positive rail. Next, route the next wire to the second transistor collector. Last, connect the remaining wire to the potentiometer bridge you create in the previous step.
Solder the AM coil
Now it’s time to connect the RF coil to your circuit. Since this is a tank circuit, you must place the AM coil collateral to the trimmer capacitor. Connect the two by attaching one lead to the insulator and the other to the variable capacitor.
Audio jack connection
To finish, you will need to connect the audio jack or speaker to your AM radio circuit. Install a 3.5 mm audio jack between the collector and positive rail by soldering it. You will also need to solder the positive rail from the battery slot to the diode’s positive anode. Next, attach the negative connection to the female jack’s third pin.
An amplitude modulation radio is quite easy to put together through the use of some basic electrical components. Following our guide, you can create your own AM receiver with absolute ease. Find a circuit drawing to follow so that you can prepare your material list and circuit layout accordingly. Our detailed instructions should help you create your own fully functional radio to tune into nearby AM stations.
You can also read our article on making AM radio antennas if you want to build an antenna yourself.