Wxdc12003 Schematic Better -

💡 : If you are experiencing instability, add a 100nF ceramic capacitor and a 100uF electrolytic capacitor in parallel across the 5V output to smooth out high-frequency switching noise.

An optocoupler provides a feedback loop from the output side to the controller on the primary side, maintaining a stable 5V even as the load changes. wxdc12003 schematic better

We tested three configurations: