022EN Arduino Piano Part 2 - Audio Amplifier Output Stage

Building an Arduino Piano Part 2 - Audio Amplifier Output Stage

The various audio amplifier classes are presented with their advantages and disadvantages:
- Class A
- Class B
- Class AB
- Class H
- Class G
- Class D

Calculations are carried out for class B and AB and real amplifiers are set up and measured. For class AB amplifiers, the cross current and the temperature dependence of the cross current are discussed and a simple protection is presented.

The measurements are carried out in both the time and spectral domain. At the end of the video there is a sound comparison between B and AB amplifiers.

Supplementary Videos:

Superposition principle
https://youtu.be/hzrUSL-43J4

Current limitation by emitter resistance
https://youtu.be/t2MdVmGXgwg

Change in base-emitter voltage with temperature
https://youtu.be/5lyAbJo7rZ8

0:00 Introduction
0:24 Content
0:46 Amplifier class overview
1:24 Class A amplifier review
2:35 Class B amplifier review
4:52 Class AB amplifier review
5:55 Class G amplifier review
7:44 Class H amplifier meeting
9:09 Class D amplifier meeting
12:18 Boundary conditions and data sheet information for the calculations
14:02 Calculation class B amplifier
16:09 Experimental setup class B amplifier
17:02 Time domain measurement Class B amplifier
18:00 Spectral range measurement Class B amplifier
19:01 Calculation class AB amplifier - cross current problem
20:13 Calculation class AB amplifier - cross current protection
23:25 Calculation class AB amplifier - determine temperature increase
28:19 Calculation class AB amplifier - R1 and R4
29:10 Calculation Class AB Amplifier - Max Iin
29:49 Calculation Class AB Amplifier - Unipolar Supply Voltage
30:15 Calculation class AB amplifier - output electrolytic capacitor
31:35 Experimental setup class AB amplifier
32:55 Time domain measurement class AB amplifier
34:34 Spectral range measurement Class AB amplifier
35:50 Class B and AB amplifier sound comparison
36:07 Final message