Though LM386 audio amplifiers are very old. But they still have a lot of useful.
Thanks, designer.
Imagine your audio player is weak sound. You want to increase sound up. They are a good choice. Because of the low voltage supply and work well with a battery.
LM386 Datasheet
You finished an audio circuit. But the sound is too weak.
Many people use LM386 to increase sound up to a speaker. Why should you do it too? Some said to try it now.
But…it is better. If you read LM386 Datasheet before.
LM386 is a low voltage audio amplifier. And, good at working with a battery. Its shape is similar for IC-741, DIP-8. So, small and easy. Even small but great sound.
Cr: LM386 of National Semiconductor. I like it.
LM386 Pinout
Often we use LM386 in DIP-8. Which there are a few pin connections. Even other packets are the same. For example, SOP-8, TSSOP-8, etc.
See LM386 Features
- Give enough power—Common Power of the output is about 700mW at VS=9V, RL=8Ω, THD=10%. Imagine you can listen to soft music at prefer corner.
- Use Wide supply voltage range of 4V to 15V.
- Use low supply current—if no input signal is approx 4mA or max 8mA.
- Internal voltage gain set to 20 or 26dB. (without other parts)
- The more voltage gain to 200 or 46dB. When we connect a 10uF capacitor across pin 1(+) and pin 8(-).
- And, we may use a resistor in series with the capacitor. To reduce the gain between 20 and 200.
- Low harmonic distortion: 0.2% typical
- Frequency bandwidth: 300kHz in typical
With a lot of their benefits. A lot of electronic appliances have it to drive the speakers. Example for, radio, MP3 player, Mini Portable speaker, Etc.
More circuit more understand
My brain is slow. I cannot understand any information fast. Has this happened to you?
I have used images. They help me understand anything more.
Also, I like the circuit diagram and circuits. I see and learn and get many ideas from it.
So, let’s see more LM386 circuits.
x20 Amplifier
The smallest amplifier gives a gain of 20 with the least parts.
It is true. It is an amplifier circuit. Even there are one IC and one capacitor only.
And, It uses low current at the output.
But In real usage. You need a louder of sound. How do you do? You can do it in a simple way. Below.
X200 great small amplifier
In the circuit. The gain of circuit rise up to 200. Because we place the Capacitor-C2 to the IC. Connect the positive leg of C2 to Pin 1. And, the negative leg to Pin 8.
But sometimes high gain is not good for us. We can do too.
X50 lower gain of LM386 amplifier
We add another one resistor-R2 in series with C2. To reduce the gain to 50.
LM386 Amplifier with bass boost
Sometimes you may want a special bass. We also can do. Easy…with adding one resistor and one capacitor only. See in the circuit. The R2 connects with C2 in series.
This circuit is a bass booster. The output gain depends on a bass frequency. For example, Gain 25dB: 100Hz, and Gain 19dB: 2kHz.
Almost forgot some components on every amplifier above have important.
- We can adjust the volume by VR1.
- Both R1 and C3 will keep a good sound. They improve a high-frequency load for stability.
Do you know we can do other circuits with LM386?
Yes…
LM386 Square wave oscillator
We will see a square wave oscillator circuit. Also, we can create it is audible alarms on the speaker. Because this IC is on type of the op-amp. It is good at doing oscillator well.
The output frequency is approx 1KHz. We can change C2. More capacitance to less frequency.
Note: I will explain to you the working of these circuits.
In other circuits below.
What is more? Let’s build LM386 projects.
Buy LM386 at Amazon.com
Mini LM386 amplfier
If saving energy is important for you. This circuit is suitable. Because you can use it with a 9V battery at 5mA current. But give the gain of output to approx 50. Or the power of 300mW to 500mW at 8 ohms speaker.
LM386 mini audio amplifier circuit
Imagine you make an AM receiver circuit. You can use this LM386 to amplify to a speaker 0.5W, 2 inches. With a 9V battery can listen sound for long.
Flexible of choosing parts
You can use similar devices. To instead each other.
For example:
- The loudspeaker—use 4 ohms or 8 ohms. @ 0.25W or 0.5W. And any size as free space.
- Voltage supply—use 4V to 12V. And low voltage low watts. It is correct.
- The voltage of capacitors—use High voltage instead of low voltage. For example, C5 is an electrolytic capacitor. You may use 50V instead.
But… Of course, it is more expensive.
How to builds
If you want to build these circuits. You can finish them on the universal PCB or even the breadboard.
But sometimes you want a PCB board. You can make it with a PCB layout and components layout.
Figure 2 the PCB and components layout of the LM386 audio amplifier.
Parts lists
0.25W Resistors, tolerance: 5%
R1—10Ω
R2—1.2K
VR1—10K Potentiometer
Capacitors
C1, C2—0.1μF 50V Ceramic
C3,C4—10μF 25V Electrolytic
C5—220μF 16V Electrolytic
Semiconductors and others
IC1—LM386, Low voltage audio amplifier
SP1—8Ω 0.25W speaker
B1—Battery, 9V
Do you like a small Amplifier like this?
Look at more:
Buy cheap 386 Kit here
Not only that.
Look:
9V Power Amplifier using LM386
Also, the above circuit. This one of the 9V amplifier circuit diagram. I like it. Because of high gain up to 200.
LM386 mini amplifier
How it works
To begin with, the signal goes to the input pin 3, non-inverting input. This is a signal amplifier in the non-return phase form.
They have…
- The C1 absorbs this noise to protect the input.
- And C2 increases the gain of the amplifier. If you want more gain. You can add more C2 value. But, more value, too distortion (should be lower 100uF).
- The output comes out of pin 5 of IC1.
- Then, through C4 coupling the stronger audio signals to better. And DC block and not passed to the speaker.
And while both R1 and C3 in series. They keep the high-frequency response better.
Recommended: Classic active tone control circuit using ICs
Parts lists
0.25W Resistors, tolerance: 5%
R1: 10Ω
R2: 1.2K
VR1: 10K Potentiometer
Capacitors
C1: 0.01μF 50V Ceramic
C2: 10μF 25V Electrolytic
C3: 0.1μF 50V Ceramic
C5: 220μF 16V Electrolytic
Semiconductors and others
IC1: LM386, Low voltage audio amplifier
SP1: 8Ω 0.25W speaker
B1: Battery, 9V
Read Next: TDA2030 stereo amplifier circuit
500 mW Power Amplifier using LM386N
Does it use the 12V battery? Yes, LM386 can work within a car. Because of the long wide voltage supply range from 4V to 12V at 50mA only. Give power out of 500mW at 8 ohms speaker.
Some other features and the frequency response from 40Hz to 100 kHz rate. And the gain of 46 dB. And distortion Less than 1%.
How it works
First of all, Enter the power supply to the circuit. Then, LED1 lights up to show power on the circuit.
And, capacitors C6 and C7 filtered to smooth.
Then, Enter a signal to the input through C1.
It is the coupling signal to protect DC voltage noise in the circuit.
Next, the sound signal flows through VR1 to turn the volume up or down.
After that, the sound signal goes to pin 3 of IC1.
To increase the sound up. Then, the strong sound comes out of pin 5 through C5. It protects dc voltage and passes the low frequency better to power a loudspeaker.
The C4 and R1 are acting cut noise signal out away.
And, the pin 1 of IC1 has a jumper to access C3 to boost up to gain.
When the input signal is very small.
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What is more?
Parts lists
0.25W Resistors, tolerance: 5%
R1: 10Ω
R2: 1.2K
VR1: 10K Potentiometer
Capacitors
C1: 3.3μF 25V Electrolytic
C2, C6: 0.1μF 50V Ceramic
C3: 10μF 25V Electrolytic
C4: 0.047μF 50V Ceramic
C5: 470μF 16V Electrolytic
C7: 100μF 25V Electrolytic
Semiconductors and others
IC1: LM386N4, Low voltage audio amplifier
LED1: Red LED 5mm.
SP1: 8Ω 1W speaker
B1: Battery, 4V to 12V
Download This Post as a PDF and all PCB layouts
Conclusion
We love LM386, me too. Because it uses a battery. We can test and make them more. It is easy and cheap. What do you think about it?
Sure, this may not enough for you to read more LM386
Keep Reading: LM386 Stereo Amplifier with Bridge model
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