Blue Ring Tester Schematic Diagram Exclusive -

Blue Ring Tester is a specialized diagnostic tool used primarily for testing high-Q inductive components, such as flyback transformers (LOPT), switch-mode power supply (SMPS) transformers, and deflection yokes. It works by injecting a fast voltage pulse into the component and counting the number of decaying oscillations, or "rings," it produces. Core Schematic Principles

Test a known good inductor (e.g., a 100uH choke). Slowly adjust R_Cal (the 50k trimmer) until the Green LED remains steady but the Yellow LED flickers occasionally. This is the "sweet spot" for detecting 1 shorted turn out of 100. blue ring tester schematic diagram exclusive

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The Oscillator Core:

The heart of the circuit is the HEF4069UBP (or CD4069) Hex Inverter. Blue Ring Tester is a specialized diagnostic tool

CD4069UB (Hex Inverter)

: Typically used for pulse generation and as a sensitive comparator for the ringing waveform. Slowly adjust R_Cal (the 50k trimmer) until the

Sensitivity Tuning

: A late design revision changed resistor R7 to 510 ohms to increase sensitivity for low-impedance components like horizontal deflection coils.

Add a 3-position switch to select C2 values:

in-circuit testing

The Blue Ring Tester is highly valued for because its low-voltage pulses generally do not trigger semiconductors, allowing technicians to test transformers without desoldering them from the board. However, it is not foolproof: