我的电源为何不能带负载?

你的反馈太弱了.加大反馈的电流.个人意见的. 因为我也是初学的.
就是帮你定.你试试吧.

取样电流电阻太大

同上

这个问题可多了,先检查一下有没有联错,比如连焊之类的.还有变压器有没有问题,整流管有没有倒,再就是反馈!!!

can you show your schematic?
It can be one of the following reasons:

1. The PWM driving circuit is not able to drive the transformer when on load.
2. output was connected with chips which was somewhere short.
3. Feedback control, the resistance value must be correct.