After analyzing this , we compared it against a commercial $500 LCR meter. The results were surprising:
By analyzing the decay rate (the number of "rings") of this oscillation, the tester measures the (Quality Factor) of the coil. High Q (Many Rings): Healthy component.
10-Segment LED Bar Graph (or 10 individual LEDs: 3 Red, 3 Yellow, 4 Blue/Green) Circuit Function and Node Analysis 1. The Pulse Generation and Tank Circuit
In the world of electronics repair, few tools inspire as much curiosity—and confusion—as the . For decades, technicians repairing switch-mode power supplies (SMPS), flyback transformers (LOPT), and deflection yokes have struggled with a common problem: How do you test a coil or transformer for shorted turns without expensive equipment? blue ring tester schematic diagram exclusive
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.
The circuit is designed for high sensitivity and safety, operating at low voltages that allow for in-circuit testing without damaging sensitive semiconductors. Integrated Logic:
The is a diagnostic tool used to test high-Q inductive components, such as flyback transformers (LOPT), switch-mode power supply (SMPS) transformers, and deflection yokes, by measuring their Quality (Q) factor . It functions by applying a fast voltage pulse to the component and counting the number of decaying resonant "rings" that occur; a high count indicates a healthy component, while a low or zero count suggests a shorted winding or high loss. Core Circuit Components After analyzing this , we compared it against
Unlike many testers, you can often test flyback transformers while they are still in the CRT chassis, saving hours of disassembly time [1].
For decades, professional TV repair technicians and switch-mode power supply (SMPS) specialists have coveted this tool. However, original commercial units are rare, expensive, or discontinued. This has led to a thriving underground of DIY projects. Today, we are offering something truly : a deep dive into the Blue Ring Tester schematic diagram —not just a blurry scan, but a fully analyzed, high-fidelity breakdown of how it works and how to build it.
The tester identifies shorted turns in coils that standard ohmmeters cannot detect. It works by injecting a low-voltage pulse (approx. 600–650mV) into the component and counting how many times the circuit "rings" (oscillates) before the signal decays. A higher number of lit LEDs indicates a higher Quality (Q) factor and a healthy component. 1. Technical Schematic Analysis The circuit, originally designed by Bob Parker 10-Segment LED Bar Graph (or 10 individual LEDs:
Ignition coils operate at high voltage and are prone to internal arcing (carbon tracking) which creates a shorted turn. Test them out of the vehicle with this circuit.
The coil under test (Lx) and C2 (10nF) form an LC tank. When the pulse ends, the energy stored in the magnetic field of Lx collapses, causing the tank to resonate at its natural frequency: ( f = \frac12\pi\sqrtLC ).