: 2N3904 transistors are commonly used for switching and driving components within the circuit. Functional Details
Causes the energy to dissipate rapidly, resulting in very few or no rings [1]. Exclusive Blue Ring Tester Schematic Diagram Analysis
The test probes are connected across the inductor under test ( Lxcap L sub x ). Together with internal capacitor C1cap C sub 1 , they form a parallel LCcap L cap C resonant tank circuit. blue ring tester schematic diagram exclusive
Acts as the primary inductor in the resonant circuit. Capacitor ( ): Forms the LCcap L cap C resonant tank circuit with the DUT.
to increase sensitivity for low-impedance components like SMPS transformers. Principle of Operation : 2N3904 transistors are commonly used for switching
Connect a known good inductor. The green LED should illuminate steadily. Short one turn of wire around the core. The red LED should now light.
Power / reference (if active electronics used) Together with internal capacitor C1cap C sub 1
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:
Following the above, trace the signal path:
A known-good flyback transformer primary should light up 6 to 8 LEDs. If it only lights up 1 or 2 LEDs, the component has an internal short and must be replaced.
The ringing voltage generated across the test probes is fed into the inverting input of the LM393 comparator. R2cap R sub 2 R3cap R sub 3