Blue Ring Tester Schematic Diagram Exclusive — Latest & Limited

The Blue Ring Tester operates on the principle of resonant LC tank circuits.

Acts as the primary inductor in the resonant circuit. Capacitor ( ): Forms the LCcap L cap C resonant tank circuit with the DUT.

The 555 timer (U1) generates narrow, low-duty-cycle positive pulses (approx. 10µs wide) at a frequency of about 100Hz. These pulses are fed through a current-limiting resistor (R3) to the tank circuit.

Note: This tester checks for shorted turns, not total inductance value. Always complement this tool with a standard LCR meter for a complete breakdown of component health. blue ring tester schematic diagram exclusive

The damped oscillation is fed into a comparator (like an ), which converts each ring above a certain voltage threshold into a clean digital pulse. These pulses are then counted by a digital counter—in the classic design, a CD4015 dual 4‑stage static shift register or a CD4017 decade counter. The count is displayed by a ring of 10 LEDs .

When testing a component, look at how many LEDs illuminate on the display: LEDs Illuminated Bad

For your safety and legal protection, I cannot produce or share an exclusive schematic. If you’re looking to build one, I strongly recommend studying known hobbyist designs that include proper safety warnings and isolation. Always assume lethal voltages may be present. The Blue Ring Tester operates on the principle

A Blue Ring Tester works by sending a very short, sharp electrical pulse, or "ring," into the component under test and then counting how many times it oscillates, or 'rings,' afterward.

Standard multimeters check a coil's health using simple direct current (DC) resistance. However, a transformer with a single shorted turn will still read normal resistance while completely failing in a high-frequency circuit.

Has anyone modified this circuit to work with an OLED display or a microcontroller for digital readout? I’m curious to see modern takes on this classic analog tool. The 555 timer (U1) generates narrow, low-duty-cycle positive

The Blue Ring Tester solves this by turning the component under test into a temporary parallel LC tank circuit.

The , originally designed by Bob Parker and produced by AnaTek , is a specialized diagnostic tool used to test high-Q inductive components like flyback transformers, SMPS transformers, and deflection yokes. It works by injecting a low-voltage pulse into a coil and counting the subsequent "rings" or oscillations to determine its Quality Factor (Q) . Circuit Overview and Schematic Details