rotary amplifier

例句：

1. 1.The rotary valve is used to control the flow of gases.
   旋转阀用于控制气体的流动。
2. 2.The rotary dial on the clock is easy to read.
   钟表上的旋转表盘很容易读。
3. 3. The rotary encoder is used to measure angles.
   旋转编码器用于测量角度。