One-Transistor Audio Mixer Circuit Diagram

Introduction

An audio mixer is an electronic device that is used to blend multiple audio signals into one output signal. Many audio mixers use multiple transistors to accomplish this, but the one-transistor audio mixer is a simple and effective alternative. In this article, we’ll be discussing the use of the BC109 transistor in creating a one-transistor audio mixer circuit.

Three or more inputs with individual level controls feed into the base of Q1 transistor that provides a voltage gain of 20.

Circuit Diagram

of One-Transistor Audio Mixer Circuit

This mixer amplifier can be built using a few basic components. The circuit diagram of this project is shown below.

**One Transistor Audio Mixer Circuit Diagram**

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Components List

of One-Transistor Audio Mixer Circuit

BC109 Transistor x 1
5uf Capacitor x 2
100uf Capacitor x 1
22k Resister x 3
2.2k Resister x 1
1M Resister x 1
10k Potentiometer x 3

Explanation of One-Transistor Audio Mixer Circuit

BC109 Transistor: The BC109 is a small-signal, low-noise NPN transistor. It has a gain of around 200 and is commonly used in audio applications such as preamplifiers and amplifiers. In an audio mixer circuit, the BC109 can be used as the sole amplifying element, making for an easy and inexpensive design.

One-Transistor Audio Mixer Circuit: The audio mixer using a BC109 transistor consists of just a few components. The input signals are connected to the base of the transistor through the capacitor, which blocks any DC components. The variable resistor allows for adjustment of the volume levels, and the resistors around the transistor bias it into the linear region of operation. The output is taken from the collector of the transistor via capacitor, which is connected to a load such as headphones or a speaker.

Conclusion of One-Transistor Audio Mixer Circuit

The one-transistor audio mixer circuit using a BC109 transistor is a simple and effective design that can be used for small-scale audio mixing applications. It requires only a few components and is easy to build, making it a great option for hobbyists, students, and DIY enthusiasts. However, it may not be suitable for larger-scale mixing applications or those that require a high level of precision or fidelity. Overall, the BC109 transistor is a great choice for those looking to create a basic audio mixer.