Audio conversion to light LED circuits converts sound energy from the environment to electrical energy. The circuit is a combination of transistors, resistors, capacitors, LEDs, and an electret microphone.
Hardware Components
The following components are required to make Audio Conversion to Light LED Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Transistor | 2N4401 | 3 |
| 2. | LED | – | 4 |
| 3. | Battery | 9V | 1 |
| 4. | Variable resistor | 20KΩ | 1 |
| 5. | Resistor | 270Ω, 390Ω, 1.2KΩ, 10KΩ, 220KΩ, 620KΩ | 1, 4, 1, 2, 1, 1 |
| 6. | Ceramic Capacitor | 100µF | 2 |
| 7. | Electret Microphone | – | 1 |
2N4401 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of 2N4401
Audio Conversion to Light LED Circuit
Working Explanation
The circuit contains three main parts. First, an audio preamplification using transistor Q1. The electret microphone detects the sound in the surroundings and converts it into an electrical signal. This signal, then, passes through transistor Q1 to amplify. The second is an audio amplifier stage which is built around transistor Q2. Further amplification of the pre-amplified signal is carried out here. At last, transistor Q3 acts as a switching component. The signal coming out of the collector of transistor Q2 is input to the base of the transistor Q3. Hence, by activating the Q3 transistor LEDs are accordingly activated.
The 20KΩ variable resistor is responsible for adjusting the overall sensitivity of the project. Also, the circuit has the ability to work at a low voltage of 4.5V. For this case, the resistors to limit current must decrease in value. Say, for 4.5V of DC voltage, use 100Ω of resistors in place of resistors R8 to R11. Likewise, for 6V use the value of resistors R8 to R11 220Ω each. Furthermore, 5 to 10 more LEDs are optional to connect with the circuit along with the current limiting resistor.
Application
- To control the lighting of LEDs in a circuit.
- For decoration purposes
- Very common at parties for lighting decoration in sync with the music.
