The decaying AC voltage generated by the ringing coil is rectified by a fast switching diode (like a 1N4148) and fed into a series of voltage comparators. Quad op-amps or comparators like the LM324 or LM339 are ideal for this stage.
Before spending hours rebuilding a hydraulic solenoid, test its coil. A shorted turn makes the solenoid weak or erratic.
Every inductor has a quality factor (Q). When you strike a good inductor with a short current pulse, it rings—producing a decaying sine wave. The number of cycles before the signal decays to 37% of its initial amplitude is proportional to the Q factor. blue ring tester schematic diagram exclusive
+9V to +12V | +--------------+----------+----------+ | | | | [R1] [R2] [R3] [IC1] (555 Timer) | | | | +------[D1]----+----[C1]--+----------+ | | | | [Test] [Q1] [IC2] [LEDs] [Probe] (NPN) (LM311) (Ring Indicator) | | | | GND GND GND GND Use code with caution. Components List Timer (configured as an astable multivibrator). IC2: LM311cap L cap M 311
The classic AnaTek Blue Ring Tester schematic is built around a few inexpensive ICs. While I cannot redistribute the copyrighted PDF, I can describe the circuit block diagram in detail and point you to reliable sources for the full schematic. The decaying AC voltage generated by the ringing
If a shorted turn exists, the effective resistance of the coil is increased (due to eddy currents), causing the oscillation to dissipate quickly. 3. The Comparison and Display Section This section analyzes the oscillation decay.
Before we unveil the schematic, we must understand the physics. A standard ohmmeter sends a DC current through a coil. It will tell you if the wire is broken (open) or if the insulation has failed completely (short). However, it cannot detect a partially shorted turn. A shorted turn makes the solenoid weak or erratic
Protection
The result is displayed on a simple color-coded LED bar graph. While the number of LEDs may vary slightly, the principle remains the same:
To build a functional blue ring tester, a detailed schematic diagram is essential. The diagram provides a visual representation of the circuit, including the components, connections, and relationships between them. With a comprehensive schematic diagram, electronics enthusiasts and professionals can construct their own blue ring testers, customize the design, and troubleshoot any issues that may arise.
