Today, we are demonstrating a DIY project for an AM Radio. An amplitude modulated (AM) radio signals convey sound signals in the form of electrical data. These electrical data changes over to sound data with the help of some external devices. Furthermore, this sound data is encoded on the radio wave by changing the sufficiency of a high-frequency radio wave.
Hardware Components
The following components are required to make AM Radio Circuit
| S.no | Components | Value | Qty |
|---|---|---|---|
| 1. | NPN Transistor | BC548, BC549 | 1, 2 |
| 2. | Resistor | 1K, 2.2K, 10K, 35K Var, 100K, 560K | 2, 1, 1, 1, 1, 1 |
| 3. | Capacitor | 100nF, 220nF, 10nF | 2, 1, 1 |
| 4. | Headphones | – | 1 |
| 5. | Battery | 9V | 1 |
| 6. | Coil | 200uH | 1 |
| 7. | Variable Capacitor | 500pF | 1 |
BC548 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BC548
BC549 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of BC549
AM Radio Circuit
Working Explanation
In our previous articles, we talked about a basic crystal radio receiver circuit. The circuit diagram referenced here is additionally a basic AM radio circuit. Yet it isn’t utilizing a crystal, it is utilizing a high gain pre-amplifier phase of transistor BC 549 and BC 548. Moreover, the circuit is not utilizing many additional parts or components to make a good quality AM receiver. All the required components of this circuit are easily accessible in the market.
The base frequency of the electromagnetic radio wave is a lot higher than the frequency of the sound data it conveys. It is about 550kHz to 1600kHz versus 20Hz to 20kHz. Moreover, the amplitude of the carrier wave isn’t steady.
The slightly moderate variations in the amplitude make a loop that shows the frequencies in the sound signal. All together that a radio signal can convey sound or other data for broadcasting or two-way radio broadcasting, it must be adjusted or changed simultaneously. Although there are various manners by which a radio signal might be regulated, one of the easiest is to change its amplitude by varieties of sound.
Furthermore, for making 200uH curl take a #26 enameled copper wire and wound 60 turns on a 1cm diameter and 7.6cm long ferrite bar. This circuit operates with a 9-volt battery.
Applications and Uses
These days, amplitude modulation, AM is utilized for:
- Sound broadcasting on the long medium and short-wave bands
- And for two-way radio communication at VHF for airplanes
