A simple Mic audio amplifier can amplify the sound produced by a microphone. It can be used as a “Small mic and loudspeaker system” for a small place such as a room, and it is simple to construct. Besides that, this circuit can be utilized in various applications such as portable music players, radio amplifiers, television sound systems, and ultrasonic drivers, among others.
A sound sensor for microcontrollers can also be incorporated into the design. It is low-cost, low-power operated, and only requires a few components to function correctly. The LM386 integrated circuit is used to amplify sound in this circuit. The LM386 is a low-voltage audio amplifier that is widely found in battery-operated music instruments such as radios, guitars, and toys, among other things.
It is possible to amplify sound using an LM386 audio amplifier chip, which is common among users nowadays. It is frequently utilized and extremely popular. Therefore, we will cover all features of this chip in this article, including its pinouts, terminal connections, and how to integrate it into a circuit.
Steps on wiring LM386 guitar amp with a 4-ohm speaker
To successfully wire your guitar, you need to follow the steps provided. Here is a quick table with the given steps.
| Wiring steps | Functions | Essential products |
| Obtain the required parts | To ensure all components are set correctly | 1. 8-ohm speaker 2. 8-pin retention contact 3. Multipurpose PCB with 417 holes |
| Place the components | For counter check | |
| Solder all the components | To allow the connection to be tight | Soldering gun |
| Clean and test your connection | To know whether the connection was successful |
Step 1; obtain the required parts
The required parts are as follows;
An 8-ohm speaker, audio source, 8-pin retention contact, multipurpose PCB with 417 holes, resistors, and capacitors.
Check the 8-ohm speaker from Amazon
Check the 8-pin retention contact from Amazon
Check the Multipurpose PCB with 417 holes from Amazon
Step 2; place the components
Make the most use of the wiring diagram provided in the instructions to arrange the components. Even though you should try to get them as close together as possible, it is easier to stretch them out more or board this circuit first. Before soldering, I highly recommend that you breadboard the course to feel how it will function.
Step 3; solder all your components
Solder components with care to ensure no shorts, and double-check that all connections are completed at all places during the assembly. Use a soldering gun.
To know which gun I use, check the soldering gun from Amazon.
Step 4; clean and then test your connection
Make sure to clean the solder joints on the components’ leads. Make sure to double-check all connections to ensure that no links have been overlooked or missed. Connections: Connect a 5-15 Volt, the audio source, and an 8 Ohm speaker to your computer and run a few tests. Ensure you ground out the audio source’s audio line and the speaker’s wire to the circuits before connecting the two.
Pin terminals of an LM386 audio amplifier chip
The gain control of the amplifier is represented by terminals 1 and 8. A resistor and a capacitor (or just a capacitor) can be connected between these terminals to control the gain. To achieve the most significant voltage gain possible in this circuit, we will connect a 10F capacitor between these terminals.
The sound input signal terminals are located at Terminals 2 and 3. Essentially, these are the ports where you would place the sound that you would like to have amplified. Negative input is connected to Terminal 2, and positive input is connected to Terminal 3. Wire terminals 3 and 2 together to form a positive sound signal in our circuit. Terminal 3 will be connected to the ground.
Terminal 4 is designated as GND (ground), and it will be connected to the ground throughout the circuit.
The output of the amplifier is represented by terminal number 5. Amplification of the sound signal is accomplished through this connector.
Termination 6 is the terminal that receives the positive direct current voltage, allowing the operational amplifier to obtain the power to amplify signals.
Terminal 7 is designated as the Bypass terminal. This has the capability of bypassing 15K resistors. Most applications often leave this pin or link to the ground. However, a capacitor is used in our circuit for improved stability because it can avoid oscillations in the operational amplifier chip.
To know the resistors I use, check the resistors from Amazon.
Explanation of other additional components that can be used
Op-amp gain is controlled by the capacitor C1, shown in Figure 1. A capacitor can raise the gain to its maximum level, getting the highest possible gain. So the voltage flowing out of the operational amplifier is greater than the voltage flowing in.
Smoothing capacitor C2 is a capacitor that smoothes out the voltage of C1. Whenever there are any sudden voltage or current spikes in the power supply, this capacitor helps smooth out the signal and even out those spikes. This capacitor aids in the elimination of all of those ripples, resulting in less noise being introduced into the op-amp.
C3 provides a present bank for output. When the demand for current is low, this capacitor fills with electrons; nevertheless, it drains when the need for current is high.
Condensation capacitor C4 is used in coupling applications. Using this circuit removes any DC offset present at the output of the LM386 amp and passes through the alternating current sound stream.
It is possible to prevent difficulties such as oscillation by enhancing the stability of the LM386 amplifier using C5. Sounds can become unidentifiable when oscillation is used to alter them.
Conclusion
The LM386 increases the volume of the sound fed into it by a factor of 200. DC voltage is required for the operation of all amplifiers. The LM386 requires between 4 and 12 volts of direct current power to operate. Terminals 2 and 3 are used to connect the sound signal amplifier.
The sound stream is subsequently amplified and sent out through terminal 5. After connecting a few capacitors and a resistor to the signal to filter out any unwanted noise that may be present, we connect the speakers to the amplifier to playback the amplified sound.