Introduction
Do you know how to build versatile ‘LM386 Mini Audio Power Amplifier’? It can be built with the IC LM386. Very small audio signals that are low in power are unable to drive a loudspeaker loud enough to be heard by the human ear. Such low audio signals have to be amplified many times so that the signal received by the loudspeaker can deliver a sound output that is louder to hear. In order to boost the small audio signals to a great level, an audio amplifier circuit is required to deliver louder audio sound. In this task, many audio amplifier circuits are designed to work with a loudspeaker to get a large audio power output.
In the audio amplifier design circuit, many discrete transistors are used. But the latest trend is designing audio amplifiers with integrated circuits, which have many advantages over the discrete ones. Among the IC-designed audio amplifiers, IC LM 386 stands out as widely popular in terms of size, battery operation and a very few associated components, yet delivers a decent, satisfactory audio sound output.
The tiny ‘LM 386 Mini Audio Power Amplifier’ is versatile and works very efficiently for battery-operated devices. Since power consumption is small, audio amplifier gadgets can be made portable and widely used in radios, toys, and many small, handy appliances. It is inexpensive because of the low component count that goes into the design. Takes up a small space, and hence is employed in almost any gadgets.
Almost all electronics enthusiasts used to have these IC-based audio amplifiers in one or another project assembled in their labs. The LM386 is very popular and widely available.
LM 386 Audio Amplifier IC
8-Pin DIL IC in a single package. The LM 386 is a low-voltage audio power amplifier available in 8-pin DIL in a single package. The IC is designed to work with very low current and hence suitable for battery-operated devices such as radios, intercoms, and in mini DIY projects and toys. Its quiescent current is low, just 4mA. Works on a wide voltage range, 4 to 18V It provides sound output from 500 to 1 W. The gain of the IC can be adjusted to 20 to 200. It uses minimal components.
The pin connections are shown in the picture. With this, one can easily identify the circuit connections while assembling the project on the PCB.
Key Features
- IC LM386N-1 works on wide voltage range from 4 to 12V DC supply.
- Audio power output is typically from 300 to 700 milliwatts, depending on the voltage usage. 500 mW audio is optimal and excellent.
- The gain of the IC is normally set to 20. It can be adjusted to 200 with some additional components connected to pins between 1 and 8 .
- The speciality of the design is miniaturisation. As such it is widely used in battery-powered gadgets like radios, headphone amplifiers, signal boosters, etc.
- The advantage is low power consumption.
The circuit diagram
The ‘LM386 Mini Audio Power Amplifier ‘ circuit schematic is shown below. It is a very simple circuit designed with a very few associated components.
Working of the circuit
The ‘LM 386 Mini Audio Power Amplifier’ circuit is very simple in design and requires very few external components. The circuit is self-explanatory. The audio signal to be amplified is fed to the IC via the P1 input terminal. The signal is coupled to capacitor C3 and 10 K ohms Volume control to pin 3 of the IC. 8 ohms impedance Loudspeaker is connected to output terminal P2. The amplified audio signal is taken out from pin 5 via the C4 coupling capacitor. A 6V power supply is given to the IC through pin 6. Pin 4 is grounded. Low Audio signal received at pin 3 gets amplified and the amplified signal is taken out from pin 5.
LM386 parts list
| S.No | Part No. | Item | Quantity |
|---|---|---|---|
| 1 | IC | LM386 | 1 |
| 2 | C1, C3 | 10 MFD, 16V | 2 |
| 3 | C2, C4 | 220 MFD 16V | 2 |
| 4 | VR1 Volume control | 10K ohms | 1 |
| 5 | Loudspeaker | 8 ohms, 1W | 1 |
| 6 | Battery | 6V DC | 1 |
Assembling
The ‘LM386 Mini Audio Power Amplifier’ can be easily assembled on a general-purpose printed board. If one desires a PCB assembly, the exact PCB is available in the electronics mart. One can procure it and assemble it also for compactness. Except for the loudspeaker and power supply, all other components go into the relevant PCB. Use the IC socket to insert the IC.
You may be interested in building a ‘7-segment display circuit’, then read this post.
Conclusion
An efficient ‘LM386 mini audio power amplifier’ designed with IC LM386 is definitely a compact and at the same time a versatile amplifier that electronics enthusiasts build as one of the prestigious projects. Beginners surely improve their project-building skills by assembling this audio power amplifier. This audio amplifier project is a compact, handy tool for many future audio projects.
