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This project is a small circuit for a 1W amplifier which runs from a single 5V supply. It will provide 1W max into an 8 Ohm speaker at 5 volts. The amplifier is based on the TDA7052 1W BTL mono audio amplifier IC from Philips. It comes in an 8-pin DIP package making it extremely easy to solder. The circuit is very simple and requires a minimum number of components. Two of these circuits were used to provide sound output in the Viblotar.
The circuit is based on the one provided in the TDA7052 datasheet, but with added input circuitry to reduce subsonic frequencies and extremely high frequencies entering the amplifier.
The following is a parts list for the circuit.
- 1 x TDA7052 IC
- 1 x 1 nF capacitor
- 1 x 100 nF electrolytic capacitor
- 1 x 2.2 uF capacitor
- 1 x 220 uF capacitor
- 1 x 10 Ohm resistor
- 1 x 1k Ohm resistor
- 1 x 22k Ohm resistor
- 1 x 1M Ohm resistor
The 1M Ohm resistor is used to set the input impedance of the circuit. The 2.2uF capacitor and 22k Ohm resistor form a high-pass filter with a -3dB frequency of 3.3Hz to reduce subsonic frequencies and remove DC signals. The 1k Ohm resistor and 1nF capacitor form a low-pass filter with a -3dB frequency of around 159kHz to block extremely high frequency signals (such as RF interference).