
This is just another 20W audio amplifier circuit, but this time based on LM1875 audio amplifier IC from National Semiconductor. With a dual power supply 25V LM1875 can deliver 20W of audio power into a 4 ohm speaker. The LM1875 requires fewer external components and has a very low distortion. The IC is also filled with a number of cool features, like the upload speed fast, wide range power supply, high output current, high-swing output voltage, thermal protection, etc. The IC is available in TO -220 plastic power package and is very suitable for a variety of applications including audio systems, servo amplifiers, home theater systems, etc.