Speech amplifiers are compact, personal amplification systems that give voice boosts for different speech impairments. Some designs are for noisy environments, while some are ideal for simple tasks like talking. In this project, we are going to design a simple speech amplifier circuit using a TDA7052 audio amplifier IC.
Speech amplifier circuit IC (TDA7052) is a mono output amplifier, which comes in an 8-lead DIP package. The device mainly caters to battery-operated portable audio circuits. The features of TDA7052 IC include; no need for extra components, no on/off click sounds, great overall stability, very low power usage, low THD, no heat sinks required & short-circuiting proof.
Hardware Components
The following components are required to make Speech Amplifier Circuit
| S.no | Component | Value | Qty |
|---|---|---|---|
| 1. | Breadboard | – | 1 |
| 2. | Connecting Wires | – | 1 |
| 3. | Battery | 9v | 1 |
| 4. | Amplifier IC | TDA7052 | 1 |
| 5. | Transistor | BC547 | 1 |
| 6. | Polar Capacitors | 220μF, 10μF | 2, 2 |
| 7. | Microphone | – | 1 |
| 8. | Speaker | 8 ohm | 1 |
| 9. | Mono Jack socket | 3mm or 6mm | 1 |
| 10. | On/Off slider switch | – | 1 |
| 11. | Potentiometer | 22KΩ | 1 |
| 12. | Resistor | 1MΩ, 15KΩ, 470KΩ, 4.7KΩ | 2,2,2,2 |
| 13. | Ceramic Capacitor | 100nF, 10nF | 2, 2 |
TDA7052 Pinout
For a detailed description of pinout, dimension features, and specifications download the datasheet of TDA7052
Speech Amplifier Circuit
Working Explanation
The heart of the circuit is a TDA7052 Audio power amplifier IC, delivering a maximum output of 1.2W at a 6V supply. An external microphone must be plugged into J1, its signal is amplified by Q1 and fed to IC1. R1 acts as volume control and C3 controls the upper audio frequency band, mainly to reduce the microphone’s possibility of picking up the loudspeaker output, causing a very distinct and loud howling noise, i.e. the well-known Larsen effect.
Therefore, the C3 value can be tuned in the 4nF to 22nF range in order to ensure the best compromise between speech tone quality and minimum Larsen effect interference. Dynamic or electret microphones are usually recommended. It has a useful feature that can be used to temporarily mute the microphone by connecting a toggle switch (SW1).
Applications
- Generally used in devices designed for people with deficiencies such as vocal chord damage & throat/voice problems.
- Commonly used in devices such as Low power audio amplifiers, speech amplifiers & Voice amplifiers.
