Electronics Mosfet power amplifier schematics

Description: This simple MOSFET power audio amplifier circuit, featuring a TL071C operational amplifier and two MOSFET power amplifiers, can deliver up to 45W at an 8-ohm load. The schematic is based on Siliconix applications and incorporates variations in voltage across two resistors connected in series with the voltage supply of the operational amplifier driver. The amplifier exhibits an efficiency of 70%, with distortion levels at a cut-off frequency of no more than 0.2% at 20Hz and 10W output. With a power supply of ±30V, the MOSFET audio amplifier can achieve 45W at 8 ohms and 70W at 4 ohms. It is important to note that this audio amplifier does not have short-circuit protection; therefore, it is essential to ensure that the speaker is connected before powering on the device.

The described circuit utilizes the TL071C operational amplifier, known for its low noise and high-speed performance, making it suitable for audio applications. The configuration allows the operational amplifier to drive the two MOSFETs, which serve as the main amplification stage. The choice of MOSFETs is critical, as they provide high efficiency and can handle the power levels required for audio amplification.

The resistors in series with the voltage supply play a significant role in setting the operating point and gain of the amplifier. By adjusting these resistors, it is possible to fine-tune the performance characteristics, such as the output power and distortion levels. The specified efficiency of 70% indicates that the amplifier converts a significant portion of the input power into useful output, which is essential for battery-operated or energy-efficient applications.

The distortion level of 0.2% at 20Hz is particularly noteworthy, as it demonstrates the amplifier's capability to reproduce low-frequency sounds with high fidelity. This is crucial for audio systems where bass response is critical. The amplifier's ability to deliver 45W at 8 ohms and 70W at 4 ohms provides flexibility for various speaker configurations, allowing it to be used in different audio setups.

Given the lack of short-circuit protection, it is advisable to implement additional safety measures. Users should incorporate a speaker protection relay or fuse to prevent damage to the amplifier and connected speakers in the event of a fault. Regular checks before powering on the device can help mitigate risks associated with accidental short circuits.

Overall, this MOSFET power audio amplifier circuit represents a robust solution for delivering high-quality audio amplification, suitable for various applications in home audio systems and professional setups.This simple mosfet power audio amplifier circuit, with TL071C and 2 mosfet power amplifiers can deliver up to 45W on 8 ohm. This schematic is based on Siliconix application and is based on variations of voltage on the 2 resistors serial inserted on the voltage supplier of the operational amplifier driver.

Amplifier efficiency is 70%, distortions a t cut frequency were at most 0. 2% at 20Hz on 8ohm and 10W. With a equalizer of +- 30V the mosfet audio amplifier can deliver 45W on 8 ohm and 70w on 4 ohm. Remember that this audio amplifier is not protected on shortcircuits so everytime you switch on check to see if the speaker is connected.