#### tracyyunet

##### Member

1. Output enough power P

Since P=UI, the power amplifier circuit should have a large enough voltage dynamic range and current dynamic range, which requires that the transistor can only work in the safe zone as close to the limit state as possible, which means that the power amplifier circuit is working in a large signal state Down.

2. Have the highest possible efficiency N

The so-called efficiency is the ratio of the output power Po of the power amplifier circuit to the DC power Pv supplied by the power supply.

N = Po/Pv x 100%

Obviously, the larger the ratio, the higher the efficiency. Considering that the Po of the power amplifier circuit is relatively large, the improvement of efficiency means the reduction of DC energy consumption.

3. There is as little nonlinear distortion as possible

Since the transistor works in a large-signal state, it is inevitable that the signal will enter the nonlinear region and cause nonlinear distortion. Generally, the higher the output power, the higher the probability of non-linear distortion.

According to different occasions, the requirements for nonlinear distortion are different. For example, in industrial control systems, the main purpose is to output power. In order to increase the output power, a small distortion will be allowed within a certain range. For measurement systems and electroacoustics equipment, it is necessary to avoid nonlinear distortion as much as possible.