At this In this article, I will show you how to make lm386 audio amplifier. It uses few external components and can be made at very low cost. cost and size, LM 386 amplifier provides a clear and loud sound.
Audio circuits using LM 386 IC can be designed in many ways but most of them produces noise. The circuit provided in this article is properly designed and has minimum disturbance.
The power output of LM 386 audio amplifier is 1 watt at max. It is a low power circuit, still it can be used for wide range of purpose.
Some examples are –
- Mini portable speakers
- Toys
- Laptop or mobile audio amplifiers
Components Required
The components required for lm386 audio amplifier are –
- LM 386 IC
- 47 µF / 25v capacitor
- 10 µF / 25v capacitor
- 100 µF / 25v capacitor
- 220 µF / 25v capacitor
- 100 nF capacitor X 2
- 47 nF capacitor
- 10 Ω,25 W resistor
- 10 KΩ variable resistor
- 5 mm audio connector
- 4 Ω speaker
- 5 – 9 v power supply
- Breadboard / vero board
- Connecting wires
lm386 pinout
Circuit diagram
The circuit diagram of lm386 audio amplifier is shown below –
Tutorial
Follow these steps to make connections
- Connect the positive terminal of 47 µF to pin 1 and negative terminal to pin 8.
- Now short pin number 2 & 4, then connect it to negative terminal of the power supply.
- Look at the diagram of variable resistor shown below. Connect its W terminal to pin 3 of ic. Now connect one terminal of 100 nF capacitor to terminal A of variable resistor. The other terminal of capacitor will be connected to positive ( middle ) terminal of 3.5mm audio connector. The other terminal of audio connector is connected to terminal B of variable resistor. Also terminal B is further connected to pin 4 of IC.
- The 100 nf and 100 µF capacitor is connected in parallel to power supply.
- The positive terminal of power supply is directly connected to pin 6 of IC.
- Connect the positive terminal of 10 µF capacitor to pin 7 of IC. The negative terminal of capacitor is connected to negative terminal of power supply.
- Now make a series connection of 47 nF capacitor and 10 Ω Connect the resistor side to pin 5 of IC and the capacitor side to negative terminal of power supply.
- Take 220 µF capacitor and connect its positive terminal to pin 5 of IC. Then connect the negative terminal of capacitor to positive terminal of 4 Ω
- Lastly, connect the negative terminal of speaker to negative terminal of the power supply.
Working of lm386 audio amplifier
lm386 audio amplifier is simple and efficient. The working of this circuit is simple as majority of the work is done by IC itself.
When the power supply is turned on and a clear audio signal is provided to the circuit. The IC amplifies the input audio signal by a factor of 200 and plays it in the speaker connected in the output.
To get the best output from circuit, make sure you make proper and tight connections. Any audio circuit with loose connections can create a lot of noise in the output.
Working of LM 386 IC
LM 386 is class AB audio amplifier IC. It is used in wide range of applications. LM 386 IC creates a low power amplifier. Its low input power make it suitable for portable speakers that are battery operated.
The table below shows the function of each pin of LM 386 IC.
|
Pin Number |
Pin Name |
Function |
|
1 |
Gain |
Gain setting |
|
2 |
-ve input |
Inverting input |
|
3 |
+ve input |
Non inverting input |
|
4 |
GND |
ground |
|
5 |
V out |
output |
|
6 |
Vs |
Power supply |
|
7 |
Bypass |
Bypass decoupling path |
|
8 |
Gain |
Gain setting pin |
The gain of LM 386 IC is set to factor of 20 by default. The capacitor between the terminals 1 and 8 bypasses the internal resistor and is responsible to increase the gain to 200.
The pins 2 and 3 are inverting and non-inverting inputs. The audio signal input is provided to IC through these pins.
The pins 4 and 6 are generally connected to power supply. Where pin 4 is connected to -ve terminal and pin 6 is connected to +ve terminal.
The pin 7 makes the path for decoupling. A capacitor needs to be connected between pin 7 and ground.
Lastly, pin 5 is the output pin. The output signal is properly filtered using capacitors ( to prevent DC ) and then provided to speaker. DC signals can easily damage the speaker.
Applications of LM386 Audio amplifier
The common applications of lm386 audio amplifier are –
- Battery operated speakers
- Mini portable audio amplifiers
- Television sound system
- Laptop / mobile sound system
- Toys
Author
Akash Sharma
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