你好，E，
正如你所见，Vd1 和 Vd2 在仿真中是正弦波，示波器上显示的是绿色和黄色。仿真还显示 LT1028 的输出应该是正弦波，峰峰值 9V。但我在示波器上看不到 LT1028 的正弦波。只有一条 15.5V 的直线，也就是蓝色的那条。我不知道它出了什么问题。

 

Hi, lan,
Yes, they are NPN transistors, 2N1711S. These two transistors used as a current source to provide steady current for JFET source.
Y

 

hi YYY,
Please post a photo of the circuit board, so that we can check the connections and components

E

 

Hi, E,
Thanks for your help, problem solved. The LT1028 is faulty. I changed a new one and the wave appears. Thank you!!

 

hi YYY,
That's good news.

Good luck with your project.
E