The device uses a sequence of eight tri-color LEDs to represent the number of oscillations (rings) detected when a test pulse is applied to a coil. This allows for a fast "go/no-go" diagnosis that a standard ohm meter cannot perform. Ring tester for Coils and Transformers.
The Blue Ring Tester is the gold standard for testing high-Q inductive components. It accurately identifies shorted turns in flyback transformers, deflection yokes, and switch-mode power supply (SMPS) transformers.
: A momentary push-button switches a current pulse through a
: Moderate dampening. The coil may have a partial short, low Q-factor, or iron-powder core degradation. Further testing is advised. blue ring tester schematic diagram exclusive
Blue Ring Tester Schematic Diagram Exclusive: The Ultimate DIY Guide
Despite its utility, the Blue Ring Tester has important limitations:
The coil is healthy, has high inductance retention, and no shorted turns. Construction and Calibration Tips The device uses a sequence of eight tri-color
In a healthy coil, the energy rings down slowly over several cycles (high Q). If a short exists, it acts as a heavy load, absorbing the energy and causing the ringing to collapse immediately (low Q). Core Blocks of the Schematic Diagram
When a good inductor is pulsed with a voltage, it creates a "ringing" effect—a decaying sinusoidal wave. If there is even one shorted turn in the winding, the energy is absorbed, and the ringing is instantly damped or eliminated. Key Applications
Produces a long series of damped oscillations (rings) when pulsed. The Blue Ring Tester is the gold standard
By dumping a brief pulse of current into a coil, this device measures how long the component "rings" (oscillates). Shorted turns drastically reduce these oscillations, which the tester displays via a row of LEDs.
This pulse excites the inductor, causing it to "ring" at its resonant frequency.
The coil is functional. Lower readings are common for smaller inductors or specific yoke windings.
The "Exclusive" secret to the Blue Ring Tester’s accuracy lies in the . Because inductors can kick back high voltage, the schematic incorporates high-speed clamping diodes (like the 1N4148) to protect the sensitive comparator inputs without dampening the natural ring of the component. Step-by-Step Testing Procedure