A single Transistor Audio Mixer Circuit is an important part of audio devices. It is commonly known as Audio Mixer. The circuit is commonly used to mix two or more audio signals in one (mono) or two separate outputs (Stereo).
This device is commonly used in concerts, movies, the music industry, television, etc. Here we will learn a simple audio mixer that will combine three audio signals into one using a single transistor.
Hardware Components
The following components are required to make Audio Mixer Circuit
| S.No | Component | Value | Qty |
|---|---|---|---|
| 1. | Power Supply | 12v Dc | 1 |
| 2. | NPN Transistor | 2N2222A | 1 |
| 3. | Resistors | 4.7k, 3.9k, 2.2M | 3, 1, 1 |
| 4. | Capacitors | 1uF, 470pF, 22uF, 100uF | 3, 1, 1, 1 |
| 5. | Three separate audio signals for mixing | – | 1 |
2N2222 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N2222
Audio Mixer Circuit
Working Explanation
In this circuit, the heart of the device is the 2N2222A NPN transistor. 12V DC power supply can be used to power the circuit. There are three audio inputs following DC blocking capacitors and then resistors, passing through the transistor. There is a filtering circuit after the transistor to provide a smooth audio output without any noise. By connecting the output wire with the input of the speaker, we can listen to the audio with will be combined from all three inputs.
