An audio amplifier is a circuit that transforms the small amplitude of audio input signals into a large amplitude audio signal at the output. The basic example of the audio amplifier is the mic circuit.
This article is about making an audio amplifier using TDA7294 IC. It is designed as a class AB amplifier. It has great ripple rejection. The IC supports low noise and distortion. It protects the short circuit as it has a built-in thermal shutdown. However, the circuit requires a heat sink. The frequency response for the integrated circuit is 20Hz to 20KHZ. For the load in the circuit, use an 8-ohm and 15-watt speaker. Remember to use a filtered power supply. Because ripples in the supply can cause oscillations.
Hardware Components
The following components are required to make Audio Amplifier Circuit
| S.o | Components | Value | Qty |
|---|---|---|---|
| 1. | PCB | – | 1 |
| 2. | IC | TDA7294 | 1 |
| 3. | Electrolyte Capacitor | 10uf, 22uf, 47uf, 1000uf, 100nf | 2, 2, 1, 3, 2 |
| 4. | Resistor | 2.7ohm, 680ohm, 10K, 22K | 1, 1, 1, 3 |
| 5. | Speaker | 8ohm/ 150watt | 1 |
TDA7294 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of TDA7294
Audio Amplifier Circuit
Working Explanation
VM in the circuit is the mute ON and OFF voltages which are equal to 1.5V and 3.5Volts respectively. VSTBY is the standby ON and OFF voltages which Are equal to 1.5 volts and 3.5 Volts respectively. Capacitor C8 is working as the input coupling capacitor which is connected to the non-inverting pin of the IC. Capacitors C10C10 and C4 are the bypass capacitors. While C9 and C3 are filter capacitors for the power supply. S1 and S2 are the mute and standby switch respectively. C2 which is shorted between pin 14 and pin 6 is the feedback capacitor. Speaker is connected at pin 6 of the IC as the load.
Application and Uses
- In-home audio systems
- For Hi-fi devices
- In the Toys
- Can be used in Military equipment
- In robotic circuits
