Three-Input Microphone Preamplifier Circuit - LM348

Introduction

Voice-activated or sound-activated circuits that are commonly known as mixer circuits are used to attenuate the sound of any microphone in the systems. In simple words, this is the circuit that reduces the volume or the sound level of the unaddressed microphone. Therefore, can be utilized in courtrooms, parliament, etc. Certainly, it maintains noise and reverberation in the background. In this article, we will make the three-input microphone preamplifier. As we all know the preamplifier is the initial stage of any amplifier circuit that increases the magnitude of an audio signal. Also, It helps to reduce distortion. Thus, the circuit is effective to implement.

To make this circuit, it is preferable to use the high-quality PCB Board. Also, it is necessary to operate the circuit with the regulated and filtered dual power supply.

Hardware Required

Circuit Diagram

Working Explanation

Three input microphone preamplifier circuit contains the four LM 348 IC. The internal structure of an IC contains four operational amplifiers. Here, three of them are used to take input from the microphone channels. While the fourth one takes the output coming from those amplifiers. This fourth amplifier works as a mixer and mixes all signals. That's how it drives the IC.

Application and Uses

• It can be used in video conferencing.
• The circuit can be utilized in courtrooms.
• Also, for the panel discussion.
• In the hotel sound systems.