15W Power Amplifier Circuit Diagram

Introduction

A 15-watt low-distortion power amplifier is a crucial component of any audio system that requires high-quality sound reproduction. The 15W Power Amplifier Circuit Diagram is the blueprint that guides the construction of this essential component. This article will delve into the circuit diagram of the 15-watt low distortion power amplifier, focusing on the NSP5194 PNP and NSP5191 NPN transistors used in the output, LM378 IC used in audio, and the 13-volt power supply required.

The NSP5194 PNP and NSP5191 NPN transistors are the critical components in the output stage of the 15-watt power amplifier circuit. These transistors are chosen due to their high gain, making them suitable for use in the output stage. The output stage of the circuit provides the power required to drive the speaker. To understand how the NSP5194 PNP and NSP5191 NPN transistors work in the output stage, we must first examine their characteristics.

The NSP5194 PNP transistor has a maximum collector current of -2A and a maximum power dissipation of 15 watts. It also has a high current gain of between 70 and 700. The NSP5191 NPN transistor, on the other hand, has a maximum collector current of 2A and a maximum power dissipation of 15 watts. It also has a current gain of between 100 and 700.

Circuit Diagram

of 15W Power Amplifier Circuit

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The NSP5194 PNP transistor and NSP5191 NPN transistor are used in a complementary-symmetry amplifier configuration. In this configuration, the NSP5194 PNP transistor conducts when the input signal is negative, while the NSP5191 NPN transistor conducts when the input signal is positive.

Working Explanation

of 15W Power Amplifier Circuit

To bias the output stage of the 15-watt low-distortion power amplifier, a voltage divider network consisting of two resistors is used. The resistor connected between the collector of the NS5191 NPN transistor and the power supply is the load resistor. The value of this resistor depends on the required output power and the speaker impedance. The resistor connected between the collector of the NSP5194 PNP transistor and the ground is the bias resistor.

To achieve low distortion, a feedback loop is used in the circuit. The feedback loop connects the output of the power amplifier to the input of the LM378 IC, which is used as the pre-amplifier. The LM378 IC is a low-noise, high-gain pre-amplifier that provides a clean amplified signal to the power amplifier. The input signal to the pre-amplifier is provided through a coupling capacitor, which blocks the DC component of the input signal, ensuring that only the AC component is amplified.

The output of the LM378 IC is connected to the input of the power amplifier through another coupling capacitor. This coupling capacitor blocks the DC component of the output signal, ensuring that only the AC component is amplified by the power amplifier. The output of the power amplifier is then rectified through a diode and filtered through a capacitor to provide a clean DC power supply to the LM378 IC.

A 13-volt power supply is used to provide the necessary voltage to the circuit. The power supply consists of a transformer, a bridge rectifier, and a smoothing capacitor. The transformer is used to step down the AC voltage to the required level, after which the bridge rectifier converts the AC voltage to DC voltage. The smoothing capacitor smooths the DC voltage to ensure that the voltage supplied to the circuit is clean and stable.

Conclusion

In conclusion, the circuit diagram of a 15-watt low-distortion power amplifier using NSP5194 PNP and NSP5191 NPN transistors in the output stage, LM378 IC in the pre-amplifier, and a 13-volt power supply provides a clean, high-quality audio signal output. The circuit design relies on the complementary symmetry amplifier configuration of the PNP and NPN transistors in the output stage, as well as the use of a feedback loop for low distortion. When properly assembled and calibrated, this amplifier provides a superior audio output unmatched by traditional DIY audio systems.