This simple and budget-friendly Low Cost AM Radio Receiver Circuit has a easy design that helps you catch regular AM radio signals.
It uses common components such as the 2N3904 transistor and the LM386 audio amplifier chip to effectively locate and enhance AM signals.
This project is perfect for beginners and anyone curious about electronics, as it shows the fundamental concepts of amplitude modulation and radio frequency detection.
You can conveniently power the circuit with a 9V PP3 battery.
Circuit Working:
Parts List:
| Component | Specification | Quantity |
|---|---|---|
| Resistors (1/4 Watt) | 100k, 10k | 1 each |
| Potentiometer | 10k | 1 |
| Capacitors | Ceramic 100nF | 3 |
| Trimmer capacitor 365pF | 1 | |
| Electrolytic 100µF 25V | 1 | |
| Electrolytic 220µF 25V | 1 | |
| Semiconductors | IC LM386 | 1 |
| Transistor 2N3904 | 1 | |
| Germanium diode AA119 | 1 | |
| Inductor | AM Antenna Coil | 1 |
| Antenna | 100cm metal wire | 1 |
| Headphone | – | 1 |
| On/Off Switch | – | 1 |
| Power Supply | 9V Battery | 1 |
The working of this Low Cost AM Radio Receiver Circuit is very simple to design.
The antenna is designed to catch AM signals, which are then refined by an LC tank circuit that has an antenna coil L1 and a trimmer capacitor C1.
This tank circuit helps select a specific frequency from the AM range.
Once the signal is detected it passes through a diode D1 that demodulates the AM signal extracting the audio component.
Capacitors C2 and C3 serve as filters smoothing the signal and eliminating any unwanted high frequency noise.
After that the signal goes to the base of transistor Q1 which amplifies the weak audio signal.
This stronger signal then travels through capacitor C4 which blocks any DC components before reaching the IC1 LM386 audio amplifier chip.
The LM386 is made to further amplify the audio signal, which is ultimately sent to the headphone.
Capacitors C5 and C6 play a crucial role in filtering and decoupling ensuring that the amplification remains free of noise.
The entire circuit operates on a 9V battery, which can be turned on and off using switch S1.
Formulas:
Below are the formulas for Simple Low Cost AM Radio Receiver Circuit:
Tuning Frequency of LC Circuit:
f = 1 / (2 * π * √(L * C))
where,
- f is the resonant frequency in hertz Hz
- π (pi) is a mathematical constant of 3.1416
- L is the inductance in henries H
- C is the capacitance in farads F
How to Build:
To build a Simple Low Cost AM Radio Receiver Circuit follow the below mentioned steps for connections:
- Gather all the components as mentioned in the above circuit diagram
- Connect pin 2 and pin 4 of IC1 LM386 to the GND of the circuit
- Connect pin 3 of IC1 to center pin of VR1 pot and upper pin of VR1 is connected to one end of capacitor C4 and lower pin of VR1 is connected to GND
- Connect pin 6 of IC1 to positive supply of the circuit
- Connect pin 5 of IC1 to positive of capacitor C5 and negative of capacitor C5 connect to one end of headphone and other end of headphone connect to GND
- Connect the collector of transistor Q1 to the junction of resistor R1, R2 and capacitor C4
- Connect the base of transistor Q1 to capacitor C3 diode D1 and Antenna in series
- Connect capacitor C2 between capacitor C3 and diode D1 and GND
- Connect Trimmer capacitor C1 between Antenna and anode of diode D1
- Connect L1 inductor parallel to capacitor C1
- Connect positive of capacitor C6 to positive supply and negative of capacitor C6 to GND
- Connect S1 switch one end from positive supply and other end to positive of 9V battery and negative of battery connect to GND
Conclusion:
This Simple Low Cost AM Radio Receiver Circuit is a great way to begin learning about basic radio frequency circuits, how to demodulate signals and amplify audio.
It requires only a few parts but clearly shows the main ideas behind AM reception.
With this circuit enthusiasts can explore into the exciting world of analog electronics and radio communication.