9. Amplifier V1

<Intro>

In this project, I decided to try out on making a circuit that amplifies the audio signals for anyone to listen and enjoy to. Seems that I wanted a way to output audio from my PC, or even work on projects that require using an amplifier as a sound source. Either way, having an amplifier can be useful for a magnitude of functions, since it's all about amplifying the signal from the input source to the output.

<Operation>

To start with, I utilized the LM386 chip, which can amplify the sounds while also being energy efficient-using voltages from 5 volts to 9 volts in order to drive a speaker up to 1 watt. The only flaw with this chip is that it can generate distortions when the signal is too high (in this case when the volume is too high) and that its only mono-driven, unless you use another lm386 chip to drive another speaker, making it stereo as a result. To make the output more powerful (aka making the speakers louder), connect pins 1 and 8 of the chip together with the capacitor to increase the gain from 20 to 200, thus allowing a louder sound.

<LM386 amplifier>

The circuit itself was easy to make, since having that amplifier chip means you don't need a magnitude of passive components just to drive the speaker, you just need a capacitor connected to the output of the chip and into the speaker, the capacitor for connecting the aforementioned gain pins, the capacitor and resistor for creating the Zobel network, and a variable resistor for controlling the signal from the input, essentially creating a volume control. Overall, it's a pretty nifty circuit for what it's worth, and of course useful for your daily use.

<Tidbit>

In the video below, you can see the circuit in action, but the difference is that you can hear a radio station from it, despite not using any audio source (unless you count that long piece of solder that acts like an antenna). What this tells me is that since radio waves are everywhere, it gets picked up by the long piece of solder, and without any RF-blocking components, it goes to the inputs of the chip and are then amplified so we can hear that station.

<"Radio" LM386 test>

<LM386 Amplifier>