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TDA7052 Speech Amplifier Circuit Diagram & Build Guide
Description
This circuit is designed for placement within a box alongside the speaker, creating a compact microphone amplifier primarily intended for voice amplification. This type of device is particularly well-suited for educators, presenters, tour guides, and hostesses operating in bustling, noisy environments. The core component of this circuit is the TDA7052 Audio power IC, which delivers a maximum output of 1.2W at a 6V supply. An external microphone must be connected to J1, and its signal is amplified by Q1 before being fed into IC1. R1 functions as a volume control, while C3 shapes the upper audio frequency band, mainly to mitigate the microphone's susceptibility to picking up loudspeaker output, a phenomenon known as the Larsen effect, resulting in a loud, undesirable howl. Consequently, the value of C3 can be adjusted within the range of 4n7 to 22nF to achieve the optimal balance between speech tone quality and minimal Larsen effect occurrence. Dynamic or electret microphones are strongly recommended for this application. A momentary microphone mute feature can be implemented by connecting SW1, as illustrated in the diagram.
TDA7052 Audio Power IC
The TDA7052 is a low-power audio amplifier IC commonly used in portable audio devices due to its compact size and relatively high output power. It operates efficiently with a 6V supply and provides sufficient current to drive small speakers. Its integrated protection features contribute to reliable operation and prevent damage from overcurrent or overheating. It's a popular choice for applications requiring a small form factor and decent audio performance.
Circuit Diagram:
Parts:
- P1 = 22K
- R1 = 1M
- R2 = 15K
- R3 = 470R
- R4 = 47K
- R5 = 4.7K
- R6 = 4.7K
- C1 = 100nF-63V
- C2 = 100nF-63V
- C3 = 10nF-63V
- C4 = 100nF-63V
- C5 = 220uF-25V
- C6 = 10uF-25V
- Q1 = BC547
- IC1 = TDA7052 B1
- J1 = Mono Jack Socket
- B1 = 6V Battery
- SW1 = SPST Slider Switch
- SW2 = SPST Toggle Switch
Notes:
- Handheld, unidirectional headset or ear clip microphone types are highly suitable for this device, as are Clip-on Lavaliere or Lapel microphones.
- If a small electret capsule is used for the microphone, R5, R6, and C6 must be added to the circuit to provide a power supply.
- Select a loudspeaker as large as possible to enhance circuit performance.
- Using two 4 Ohm loudspeakers wired in series or two 8 Ohm types wired in parallel will yield improved results.
- The enclosure containing the amplifier and loudspeaker(s) can be equipped with a belt and carried like a shoulder bag, or, if a smaller unit is constructed, it can be utilized as a Pick & Go Belt Clip Speaker.