uc3845flyback升降压疑问

关于uc3845的3脚电流采样的疑问

新手请教uc3845b做正激电源不能启动

电源芯片_dip-8开关电源芯片_uc3845bng dip-8 开

uc3845 (stmicroelectronics [currentmode pwm控制器]