Blue Ring Tester Schematic: Diagram Exclusive

(associated with the Dick Smith K-7205 kit), relies on a series of logic and timing stages: Blue Ring Tester Installation Guide - Inductor - Scribd

Add a BNC connector in parallel with C4 (before the comparator). Connect your oscilloscope to see the actual ringing waveform. A good coil shows >5 visible cycles; a bad coil shows 1-2 cycles. blue ring tester schematic diagram exclusive