Low Q-factor. Could be a partial short or a low-quality inductor. 6+ LEDs (Blue): High Q-factor. The component is healthy. Why This Schematic is "Exclusive"
: Flash the firmware onto your chosen microcontroller. The code simply pulls the pulse pin low for ~5–10 microseconds, waits a microsecond, activates the counter for a 2ms window, and maps the resulting pulse count directly to the number of lit LEDs.
Despite its utility, the Blue Ring Tester has important limitations: blue ring tester schematic diagram exclusive
[Pulse Generator (555 Timer)] ---> [LC Tank / Test Probes] | [LED Ring Display (4015)] <--- [Pulse Counter & Inverter (4069)] 1. The Pulse Generator (555 Timer or Microcontroller)
The circuit counts how many oscillations exceed a specific voltage threshold. Each "ring" lights one LED in the sequence. Purchasing Options Low Q-factor
: Indicate only one or two rings, signaling a shorted winding or shorted diode within the transformer. Key Technical Insights
The circuit is designed to be simple yet effective for in-circuit testing, as it uses pulses of 600 millivolts or less, which is too low to trigger most semiconductor junctions. The component is healthy
The "exclusive" feature of the Blue Ring design is the logarithmic LED driver. The circuit typically uses an LM339 or a similar quad comparator. Each comparator is set to a different reference voltage. As the ringing voltage decays, the comparators turn off one by one. triggers all LEDs (Green). Fast decay only triggers the first one or two LEDs (Red). 3. Protection Diodes
| | Ring Count (approx.) | Interpretation | | :--- | :--- | :--- | | Green | 7–10 | Good. High Q. Healthy winding. | | Yellow | 4–6 | Marginal. May work, but Q is degraded. Compare with a known good part. | | Red | 0–3 | Bad. Low Q. Almost certainly a shorted turn or a very lossy core. |