Blue Ring Tester Schematic Diagram Exclusive

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 ).

The design below is an optimized, discrete-logic variant of the classic Dick Smith Electronics (DSE) K-7205 kit. It utilizes a highly stable LM393 voltage comparator to digitize the analog ring pulses and an LED bar graph driver to display the results. Circuit Layout Description

Older schematics omit the calibration trimpot entirely. Without RV1, the tester is unreliable for different inductance ranges. Our schematic includes a in series with R5. Calibration procedure: blue ring tester schematic diagram exclusive

Blue Ring Tester Schematic Diagram Exclusive: The Ultimate DIY Guide

Many online copies of this schematic incorrectly label C4 as 100pF. Our analysis shows that 10pF is correct for the 100kHz-500kHz range. Using 100pF dampens the ring too quickly. The coil under test (Lx) and C2 (10nF) form an LC tank

Before spending hours rebuilding a hydraulic solenoid, test its coil. A shorted turn makes the solenoid weak or erratic.

Finding faults in SMPS transformers.

Always desolder at least one leg of the transformer or yoke from the circuit board before testing to prevent in-circuit components from dampening the ring.

Beyond flybacks, it is excellent for testing deflection yokes in TVs and inductor coils in audio gear. It utilizes a highly stable LM393 voltage comparator

The tester counts oscillations that exceed a specific threshold. These are then displayed as a "ring count" across the LED bar. LED Feedback: The 8 LEDs typically range from (bad/low Q) to (medium) to (good/high Q). 🛠️ Key Schematic Components