An LM386 based voiceover project circuit is a basic audio circuit that plays the microphone input signal through a speaker after being amplified by the LM386 integrated circuit.
This kind of circuit may be used to create a simple public address system, audio mixing with priority for microphone input, or even a voiceover system for presentations.
Popular for its simplicity of use, low power consumption, and high audio quality, the LM386 integrated circuit is an audio amplifier.
It has an output power of up to 1 watt for a speaker and can run on batteries with a voltage between 5V and 12V.
Circuit Working:
Parts List:
| Component Type | Description | Quantity |
|---|---|---|
| Resistors | 10k | 1 |
| Capacitors | Ceramic 0.47μF | 1 |
| Ceramic 0.1μF | 1 | |
| Electrolytic 10μF, 25V | 1 | |
| Electrolytic 470μF, 25V | 1 | |
| Semiconductors | IC LM386 | 1 |
| Diode 1N4007 | 1 | |
| Other Components | Relay 12V | 1 |
| Electret Microphone | 1 | |
| ON/OFF switch | 1 | |
| 8Ω Speaker | 1 |
In this voiceover project circuit the incoming audio signal is greatly amplified by this circuit by a factor of 200.
It only requires the IC LM386 chip and a small number of resistors and capacitors.
Together with a 10k resistor, two bigger capacitors about 10μF and 470μF and a smaller one around 0.047μF make up the primary power amplification portion.
A snubber circuit consisting of an additional resistor and capacitor about 0.047μF and 10k helps control the speaker, which functions similarly to an electrical magnet.
The circuit may operate with speakers that have resistances ranging from 4 to 32Ωs and requires a power supply between 5V and 12V.
Two of the eight connection ports on the IC1 LM386 chip pins 1 and 8 are dedicated to regulating the gain.
A C2 capacitor is positioned between these two pins in our design.
The chip sets the total amplification to 200 times with this capacitor setting.
For prototype purposes, you may construct this circuit on a breadboard, for a more durable solution you can create a PCB.
Formulas:
The LM386 audio amplifier integrated circuit is used in the design of a voiceover project circuit to drive an 8 ohm speaker and amplify the signal from an electret microphone.
These are some fundamental and important formula for creating such a circuit:
Calculating Output Power:
One may estimate the output power Pout that is supplied to the speaker by utilizing:
Pout = Vpeak2 / 8R
where,
- Vpeak is the maximum voltage swing across the speaker (about equal to the supply voltage Vcc for an LM386.
- In this situation, 8 ohms is the speaker impedance denoted by R.
This simple circuit is appropriate for beginning voice amplification applications.
Adapt component configurations and values to individual needs, such as audio quality, power supply voltage, and desired gain.
To maximize performance and guarantee compatibility with your applications requirements, conduct tests and modifications.
How to Build:
To build a IC LM386 Based Voiceover Project Circuit follow the below mentioned steps:
- Gather all the components shown in diagram above.
- Connect pin 1 to pin 8 of IC1 LM386 through capacitor C2.
- Connect pin 2 and pin 4 of IC1 LM386 to ground.
- Connect pin 3 of IC1 LM386 to Common leg of 12V relay.
- Connect pin 5 of IC1 LM386 one end of 8 ohm speaker through capacitor C3 and other end of speaker to ground
- Connect pin 6 of IC1 LM386 to positive supply of +12V.
- Connect capacitor C1 and resistor R1 from pin 5 of IC1 LM386 to ground.
- Connect 12V rely NO leg to positive side of electret MIC through capacitor C4, and negative end of electret MIC to ground, connect NC leg of relay to audio in supply, connect one coil terminal leg of relay to ON/OFF switch, connect other coil terminal leg to ground.
- Connect a diode D1 from positive supply to ground.
Additional notes:
- The voiceover systems total sound quality will be impacted by the caliber of the speaker and microphone.
- You may also combine an external audio source with the microphone input by adding an audio input jack to the circuit with a few tweaks.
Conclusion:
A simple IC LM386 based voiceover project circuit multiplies microphone input by 200.
It is an excellent option for DIY voiceover projects because it is simple to assemble and works with a variety of power supply and speakers.
All things considered, this project circuit offers a workable option to anyone wishing to construct a basic voiceover system or a feature rich microphone amplifier.