transformer leakage inductance

2 posts / 0 new

Dear PI
I am designed a LED supply using DI-136 for 28V 1A, the out put voltage is goes high up to 40V as I increase load current 100mA voltage drop down to 25V. if i place a capacitor 3.3nF 1Kv across D7(FR305)I got 28V and good load regulation but top250 become hot.can I go for this practice? is it due to transformer primary leakage inductance? How can I measure leakage inductance? which factors are affected for leakage inductance? what functions of core cancellation winding and shielded winding in transformer? which performances effect without it? I attach schematic.

thanks & regards

Amit patel

첨부 파일Size
schematic_3.pdf562.5 KB

Amit -

Regarding the capacitor across D7, please see my response to your other forum post.


Original Post:

If you're unfamiliar with making measurements of transformer parameters, this is a very good article:

-The Traveler