If you repair switch-mode power supplies (SMPS), you know the "Blue Ring Tester" is the gold standard for quickly identifying shorted windings in high-frequency transformers and inductors. While many kits exist, the schematic is often hard to find or low quality.
For those building this on perfboard or wanting to understand the magic, here is the signal flow: blue ring tester schematic diagram exclusive
Understanding the Blue Ring Tester: Exclusive Schematic Diagram and Circuit Guide If you repair switch-mode power supplies (SMPS), you