Keyestudio ESP32 Manual page 206

ESP32 Starter Kit
9.2.11 Project 8Music Performer
1. Description
In this project, we will use a power amplifier speaker to play music. This speaker can not only play simple songs, but
also perform what you desire. Thus, you can program other interesting codes in the project to accomplish splendid
learning outcomes.
2. Working Principle
The electrical signal is input from pin 1 of RP1 (adjusts signal intensity, which is also the sound volume). After coupling
in C4 and passing R5, the signal reaches IN- pin of 8002B, in which it is operationally amplified and output to BEE1
speaker.
202 Chapter 9. Scratch Tutorial