Mini audio amplifier circuit

This is a mini-sized power amplifier rated at 2 watts OTL that utilizes the LM380 integrated circuit. It serves as a ready-made circuit for audio applications and communication, requiring minimal external equipment. The capacitor C6 can be selected from a range of values between 47 µF and 470 µF to enhance bass response. Capacitor C3 is employed to attenuate high-frequency noise, with a recommended range between 0.0047 µF and 0.047 µF. The amplifier operates with a 12V power supply (ranging from 8V to 12V), which can be sourced from a car battery or other similar power sources. Pins 3, 4, 5, 10, 11, and 12 are soldered directly to the copper side of the PCB and require a heat sink for proper thermal management. This circuit represents a classic mini amplifier design that employs an op-amp audio amplifier, providing a wide frequency response. It can be adapted to convert digital signals to analog signals (DAC) and includes a low-pass filter circuit to produce audio output. The circuit is based on the LM3900 op-amp, which amplifies the signal before driving dual transistors that ultimately power the loudspeaker. Additional details can be found in the circuit diagram. This power amplifier circuit operates with a high voltage power supply of approximately 125V and incorporates both UJT and standard transistors. A transformer is utilized to step up the voltage, making it compatible with standard loudspeakers. The circuit also allows for sound enhancement through the use of a variable resistor (VR1) rated at 1M. Further details are available in the circuit schematic.

The LM380 integrated circuit is a power amplifier designed for low-frequency audio applications, offering a simple and efficient solution for small audio amplification tasks. The selection of capacitor C6 is crucial as it influences the bass response of the amplifier; larger capacitance values will generally enhance the low-frequency output, making it suitable for applications where deep bass is desired. The role of capacitor C3 in filtering high-frequency noise is equally important, as it helps maintain audio clarity by reducing unwanted high-frequency signals that could distort the sound.

The power supply requirements of 8V to 12V allow for flexibility in sourcing power, making this amplifier suitable for portable applications, particularly in automotive environments. The direct soldering of specific pins to the PCB's copper side ensures a solid electrical connection, which is essential for the reliability of the amplifier's performance. The inclusion of a heat sink is critical, as the LM380 can generate significant heat during operation, especially when driving loads like loudspeakers.

The circuit's design also allows it to interface with digital-to-analog converters (DACs), making it versatile for modern audio applications. The LM3900 op-amp serves as the initial amplification stage, providing a high gain that is necessary for driving subsequent transistor stages. The dual transistors are configured to handle the higher power demands of the loudspeaker, ensuring that the output is both powerful and clear.

The use of a transformer to achieve a high voltage output of 125V is a notable feature, allowing the circuit to operate efficiently with a variety of speaker loads. This design approach is typical in older amplifier circuits, which often required higher voltages to achieve the desired output levels. The presence of a variable resistor (VR1) provides an additional layer of user control over the amplifier's output, allowing for fine-tuning of the sound characteristics to suit individual preferences.

In summary, this 2-watt OTL power amplifier circuit offers a compact and effective solution for audio amplification, with features designed to enhance sound quality and adaptability for various applications. The combination of op-amps and transistors in the design ensures a robust audio performance, making it suitable for both hobbyist projects and practical audio applications.This be mini size power amplifier 2 watt OTL that use IC LM380. Be base readymade circuit for side sound work and the communication. Which use outside equipment adds least. The C6 can choose get many the value since 47uF to at 470uF which, have a voice good bass. The C3 use for decrease tall frequency or noise. It be valuable stay between 0. 0047 uF sections arrive at 0. 047uF. And use to The 12V power supply (8V to 12V) from, car battery or the other. The Pin 3, 4, 5, 10, 11 legs and 12 soldered directly with copper side of PCB. Which use replace Heat sink The detail is other, see in the circuit. This is mini old amplifier circuit that used an Op-Amp Audio Amplifier at have strip zone frequency wide. It develop upward for apply to change digital signal to analog signal circuit (DAC) and change low filter circuit.

For be born the sound of music. Which build by Chinese gambling cow staggers to stagger, By the circuit composes op-amp IC LM3900 perform amplify at the beginning, as a result driver the sound with dual transistor subsequently submit go to still a loudspeaker next. see other detail in the circuit. This be power amplifier circuit it work with high volt power supply about 125V directly. It composes UJT transistor and transistor the ordinary. This circuit uses transformer sing bail with then apply to high volt and use a loudspeaker has easy. It then get into trouble a little. You can fine to decorate the popularity has of the sound with VR1 1M. Read the detail adds in the circuit. 🔗 External reference