Simple Audio Amplifier Circuit Using LM386

Amplification is essential to improving the volume and quality of sound signals in the field of audio electronics. Due to its ease of use and efficiency in boosting audio signals, the LM386 integrated circuit (IC) has become a popular choice for audio amplifiers. This integrated circuit works especially well in situations that call for a small, affordable, and power-efficient solution.

The LM386 audio amplifier circuit is a popular option among enthusiasts, professionals, and hobbyists because of its simple construction and dependable operation. The LM386 can be a great starting point for projects involving amplifiers for educational purposes, portable speakers, and basic communication systems.

One of the most important features of this circuit is that it may be used with different electrical setups since it can run on a wide range of power supply voltages (usually between 4 and 12 volts). It also offers substantial gain, which enables users to improve weak audio inputs from sensors, microphones, and other sources.

We’ll examine the LM386 audio amplifier’s fundamental design in this circuit, emphasizing its input and output connections, gain control, and bypass capacitor for noise reduction. You’ll see how this circuit may be an essential tool for creating audio systems that achieve a balance between performance and simplicity as we go into the schematic and parts.

The LM386 audio amplifier circuit provides a compelling starting point for anyone interested in audio amplification, be they an experienced engineer looking for a dependable solution or someone just learning about electronics. Join in on this learning journey with us as we disassemble the parts, go through the theory of operation, and walk you through building a reliable audio amplifier with the LM386 IC.


Audio Amplifier Circuit Using LM386

Circuit Schematic

Audio Amplifier Circuit Using LM386


  • LM386 Op-Amp IC
  • 1000 uF/25V Capacitor
  • 100 uF/25V Capacitor
  • 10 uF/25V Capacitor
  • 220 uF/25V Capacitor
  • 0.1 uF Ceramic Capacitor
  • 10 KΩ Potentiometer
  • 10 Ω Resistor
  • 8 Ω Speaker
  • 9V Power Supply
  • Jumper Wires
  • Breadboard

Circuit Connection

Pin 6 connects the IC directly to the positive power source, and Pin 4 connects the IC directly to the ground. The audio frequency is supplied to the non-inverting pin 3, while the inverting pin 2 is normally grounded. A 3.5 mm coaxial cable can be used to input this audio signal. To adjust the volume, a 10 KΩ resistor is additionally connected in series with the audio signal.

The amplifier’s gain is adjusted using pins 1 and 8 on the amplifier integrated circuit. The maximum gain of 46 dB can be obtained by connecting a 10 uF capacitor across the pins, but you can bypass them for the default gain of 26 dB. To prevent unnecessary oscillations, a 0.1 uF filtering capacitor is connected to pin 7. The output pin 5, which is linked to an 8 Ω speaker, provides the amplified audio signal. Additionally, a 220 uF filtering capacitor is connected to it.

Working Principle of Audio Amplifier Circuit

The circuit that uses this LM386 op-amp operates in a very simple way.

The LM386 amplifier turns on the entire circuit and powers the output speaker when the circuit is turned on and audio input is applied to the input terminal.

The terrible noise produced by this audio amplifier circuit diagram is one of its primary issues. However, compared to using a Vero board or PCB board, the noise level is too low when the circuit is constructed on a breadboard.

Applications of Audio Amplifier Circuit

Applications for the LM386-based audio amplifier circuit include a variety of electronic projects and systems that need to amplify audio signals. Common applications for these include:

  • Portable Audio Devices: The LM386 is commonly used in the manufacturing of portable audio equipment, including MP3 players, portable speakers, and tiny radios. It is perfect for battery-powered applications due to its small size and low power consumption.
  • Intercom Systems: Signals from microphones or other input sources can be amplified in intercom systems by using the LM386 audio amplifier circuit. Clear and loud communication is essential in these systems.
  • Educational Projects: The LM386 circuit is frequently used in educational projects to demonstrate fundamental concepts of audio amplifiers. It gives students who are studying electronics and amplification a practical experience.
  • DIY Audio Projects: The LM386 audio amplifier circuit is frequently used for a variety of audio-related projects by hobbyists and do-it-yourself enthusiasts. This can involve creating custom guitar amplifiers, audio amplifiers, or improving other electronic devices’ audio output.
  • Alarm Systems: Alarm systems that require the amplification of audio signals in order to provide effective audio quality can make use of this circuit. Alarms for fires, burglaries, or other security issues can fall under this category.
  • Sensor Signal Amplification: The LM386 circuit can be used to amplify low-level audio signals produced by sensors so they can be processed or monitored further.

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