Blue Ring Tester Schematic Diagram Exclusive Jun 2026

: Keep the traces between the test leads, the protection diodes, and the 10nF tuning capacitor as short and thick as possible. Stray inductance or resistance in these traces can artificially lower the "Q" reading.

After assembly, .

The coil is functional. Lower readings are common for smaller inductors or specific yoke windings. blue ring tester schematic diagram exclusive

The is the gold-standard DIY solution for this problem. In this exclusive breakdown, we provide the schematic diagram and explain exactly how this legendary "Q-tester" works. What is a Blue Ring Tester?

Power / reference (if active electronics used) : Keep the traces between the test leads,

Add a BNC connector in parallel with C4 (before the comparator). Connect your oscilloscope to see the actual ringing waveform. A good coil shows >5 visible cycles; a bad coil shows 1-2 cycles.

The Blue Ring Tester is a masterpiece of analog design. With fewer than 20 components, it solves a problem that stumps $10,000 impedance analyzers in certain scenarios. The we've shared today has been verified against original units and corrected for modern component availability. The coil is functional

Usually 6 to 8 LEDs ranging from Red (bad) to Blue (excellent). How the Schematic Works

Its primary purpose is to identify shorted turns, which are often undetectable with a standard resistance test because the inductance drops significantly while the DC resistance changes minutely. Blue Ring Tester Schematic Diagram Breakdown

Attach the tester leads across the primary winding of the transformer or the inductor. Read the LEDs: