Bookshelf 01 active speakers

The elements and internal function diagram are depicted in Figure 9-50. Capacitors C1, C2, and C3 represent feedback capacitance, which changes with low-frequency variations within a specific cutoff frequency range. Capacitor C5 serves as the output coupling capacitor, typically rated at 470 µF. Capacitors C6 and C7 are used to eliminate vibration capacitance without affecting performance. Capacitor C3 is designated as the power supply decoupling capacitor and should be increased in value. The TDA2822 is a dual power amplifier integrated circuit that operates at a power supply voltage of 6V, with an 8-ohm load. At a total harmonic distortion (THD) of 10%, the output power per channel is 1000 mW. The device has a low quiescent current of approximately 8 mA and includes an internal short circuit protection feature. It is designed for ease of use, allowing for the installation of four speakers in a battery-powered configuration. Additionally, a power rectifier circuit, as shown in Figure 9-52, can be utilized for active speakers powered by an external supply. A switch disconnects the power supply when not in use. When measuring the voltage at pin O of the TDA2822, it should be 1/2 of Vc. The speakers are equipped with diodes that illuminate in response to high power levels, flashing in sync with the intensity of the music signal. Another variation of the active speaker is illustrated in Figure 9-53, featuring a plastic structure with volume control and a power switch integrated into the enclosure. The circuit includes 3.3 kΩ and 2.7 kΩ resistors that form a simple surround sound circuit, as depicted in Figure 9-54, amplifying the left and right channels while removing intersecting signal components.

The schematic presented illustrates the configuration and interconnections of the components involved in the TDA2822-based amplifier system. The feedback capacitors (C1, C2) are critical for stabilizing the amplifier's gain at low frequencies, ensuring that the output remains consistent within the specified cutoff frequency range. The output coupling capacitor (C5) is vital for blocking DC components from the amplifier output while allowing AC signals to pass, thus protecting the connected speakers from potential damage due to DC offset.

Capacitors C6 and C7 serve to filter out unwanted high-frequency noise and vibrations, thereby enhancing the overall sound quality by preventing distortion. The power supply decoupling capacitor (C3) is essential for maintaining a stable voltage supply to the amplifier, especially during dynamic audio signals that may cause fluctuations in the supply voltage.

The TDA2822 integrated circuit is a robust solution for driving speakers in portable applications, given its low quiescent current and built-in protection features. This makes it particularly suitable for battery-operated devices, where efficiency is paramount. The incorporation of a power rectifier circuit allows for greater flexibility in powering the system, accommodating various power supply configurations.

The additional features, such as the LED indicators linked to the speaker output, provide visual feedback on the amplifier's performance, indicating the presence and intensity of audio signals. The design also includes provisions for user control with volume adjustment and an on/off switch, enhancing usability in consumer applications.

Overall, the circuit design integrates various components strategically to achieve a functional and efficient audio amplification system, suitable for both casual listening and more demanding audio applications. The incorporation of simple surround sound circuitry further enriches the listening experience by providing a more immersive soundstage.Elements and internal function diagram shown in Figure 9-50, c, i, C2 is the feedback capacitance t change in capacity - low frequency change within a certain range of the cuto ff frequency, C thirty, C5 is the output coupling capacitor, under normal circumstances, plus large 4 7 0r.rF can, C6.C 7 to eliminate vibration capacitance, without influence also can not, C3 for the power supply decoupling capacitors should be increased. TDA2822 is dual power amplifier integrated circuit, when the power supply voltage Vc-6V, RL. A 8fl. THD 10%, the output power per channel is lOOOmW o level when working, the quiescent current is very small, only about 8mA, and internal short circuit protector mouth considering, and often carry out regional power and easy to use, the active with speakers on battery box can be installed four on the 5th power pool, in addition, for ease of use, you can purchase a power rectifier circuit shown in Figure 9-52, is an active speaker powered speakers with an external power supply is on switch, when not in use, the switch is on the left, that is, disconnect the power mother is suspected quality problems when TDA2822 measure O, pin voltage is l/2Vc, and also on the speakers emitting diodes, high power when the light emitting diode brightness with the intensity of the music signal winking.

Another species ~ active speaker shown in Figure 9-53. The speaker for the plastic structure, volume control and power switch on the box set catchy FIG lOOn.3.3kfl in, 2.7kfl resistors form a simple surround sound circuit shown in Figure 9-54, the left and right channels and remove a section intersect signal amplification.