Circuit audio pre-amplifier integrated circuit LM358 dual op amp

The LM358 series consists of two independent, high-gain, internally frequency-compensated operational amplifiers designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible, and the low power supply current drain is independent of the magnitude of the power supply voltage. Application areas include transducer amplifiers, DC gain blocks, and various conventional op-amp circuits that can be more easily implemented in single power supply systems. For example, the LM358 series can be directly operated off the standard +5V power supply voltage used in digital systems, providing the required interface electronics without needing additional ±15V power supplies. In linear mode, the input common-mode voltage range includes ground, and the output voltage can also swing to ground, even when operated from a single power supply voltage. This circuit can be used in various situations where it is necessary to amplify low-intensity audio signals, such as in a microphone preamplifier. This version is mono, but to create a stereo setup, two equal units can be used. When assembling the amplifier, it is essential to check all connections and components for correctness. After verifying the setup, connect the circuit to a battery source ranging from 9 to 30 volts. An input signal, such as from a microphone, should then be applied, and the 470K trimpot can be adjusted to achieve a suitable signal level for the application. The trimpot allows for signal adjustment from 0 to maximum volume. To connect the input signal and the power amplifier, shielded cables should be used to minimize noise.

The LM358 operational amplifier is a versatile component widely utilized in various electronic applications due to its ability to function efficiently with a single power supply. Each of the two op-amps within the LM358 can operate independently, allowing for multiple configurations in a single circuit. The design of the LM358 incorporates internal frequency compensation, which simplifies the application of feedback and stability in amplifier configurations.

For audio amplification applications, such as microphone preamplifiers, the LM358 is particularly advantageous due to its ability to amplify low-level signals without introducing significant noise. The input common-mode voltage range extending to ground means that it can effectively handle signals that may not reach a high voltage level, making it suitable for direct interfacing with microphones.

When implementing the LM358 in a circuit, attention must be given to the power supply voltage. The device can operate efficiently at voltages as low as +5V, which is common in digital systems, thereby eliminating the need for dual power supplies in many applications. This feature promotes a more straightforward circuit design and reduces overall system complexity.

In practice, when assembling a circuit using the LM358, it is crucial to ensure that all connections are secure and that the components are correctly oriented. The use of a trimpot for volume adjustment allows for fine-tuning of the output signal, ensuring that the desired audio level is achieved without distortion. Furthermore, employing shielded cables for input and output connections is essential for minimizing electromagnetic interference, which can adversely affect audio quality.

Overall, the LM358 provides a robust solution for audio amplification and other applications, offering flexibility and ease of use in various electronic designs.The LM358 series consists of two independent, high gain, internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the pow

er supply voltage. Application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM358 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required interface electronics without requiring the additional ±15V power supplies.

In the linear mode the input common-mode voltage range includes ground and the output voltage can also swing to ground, even though operated from only a single power supply voltage. This circuit can be used in various situations where it is necessary to amplify the audio signal of low intensity, for example: How a microphone preamplifier.

This present version is mono but if you need to mount a stereo just use two equal units. When mounting the amplifier pre check all connections and components if everything is correct, connect the circuit to a battery source or in the range 90 to 30 Volts Apply an input signal that can be for example a microphone and then adjust the 470K trimpot until the signal level suitable for your application The adjuster will adjust the signal from 0 to maximum volume. To make connections to the input signal and the power amplifier to use shielded cables to avoid noise.

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