The successor to the famous Bob Parker FBT/LOPT kit and companion to the Blue ESR meter kit. This Ring Tester is an inexpensive and effective way to test any high Q inductive component. It is especially useful for doing a quick check on flyback transformers, line output transformers and other inductive components like deflection yoke windings and SMPS transformers. The easiest kit assembly ever as all components are placed on the solder masked pc board.  Assembly time will be 1 to 1.5 hours with average soldering skills. No 9V battery is included and needs to be supplied by the customer. Full Anatek 1 year warranty on component parts.


A high "Q" factor is a characteristic of low loss inductive components. A shorted turn or coil will show no rings. A shorted FBT diode will show few or no rings. The Blue ring tester gives you a measure of the "Q" factor of a inductive component.

Features of the Blue Ring Tester :

  • Supplied in kit form with full assembly with calibration instructions and manual online
  • One foot test leads made with super flexible test lead wire with crocodile clips
  • Tests inductors in circuit and test leads are non-polarized
  • Easy-to-read, high brightness red, yellow and green LEDs display the Q of the device being tested
  • Simple operation for fast easy diagnosis of faulty inductive components.
  • Ideal for testing flyback transformers, Horizontal yoke coils, B+ coils, SMPS primary windings, Fluorescent ballast/chokes and any other type of coils that have an inductance value of > 0.3 uH.
  • Includes a ferrite core and enameled wire as a test inductor
  • Kits made in Silicon Valley California, USA

See our Pinterest page for pins on Ring Testing of Inductors and Transformers.

    See a written review by Jestine Yong and refer to our discussion forum for advice on operation, assembly and de-bug

    Blue Ring Tester Video #1,  Video#2 and Video #3

    The LEDs on the left side show the Q of the device being tested. Essentially, the more LED's light up => higher Q of the device under test.

      • No lights = Short circuit
      • Red = Bad or low Q
      • Yellow = Medium Q
      • Green = Good or High Q

    From our Past Customers on the Web: 

    I'll tell you why I DO feel lucky, and that's having purchased from someone who still understands the meaning of customer service! That goes a long way in my book (well, if I had a book)" - Tod

    Works great and arrived on time. I use this with my Oscilloscope to show how ringing is produced in a coil and cap tank circuit and is useful for testing coils for shorts - Henry

    Awesome! really works, diagnosed a bad coil in 3 alternators fields in 10 minutes - Ed

    "Thank you very much for the Blue ESR and Blue RT kits. They worked out very well and I can honestly highly recommend your kits. I am very impressed with the quality of your kits and the detail that you provided to make the assembly absolutely painless" - George

    View a great informational page created by a satisfied customer - Don Lewis

    View a  review on a Ring Tester built based on the Anatek Design