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Item Category: Signal Sources & Conditioning

Bob’s Ring Tester for Inductors & Transformers, Comparable to Blue RingTester

Bob’s Basic Wide Range Ring Tester for Inductors & Transformers, Comparable to Blue RingTester, CMOS ICs Please note: The picture is just to show the measurement result. The package does not include any batteries. Overview of Bob’s Basic Wide Range Ring Tester For more information, please refer to the Youtube video. https://www.youtube.com/watch?v=BgkR4e1XfhU&t=40s https://www.youtube.com/watch?v=ZIQkxwHbHKs Design and Comparison: Bob designed a basic version of the “Blue2” microcontroller-based wide range ring tester called the basic wide range ring tester. Unlike the “Blue2,” this version utilizes 4000 series CMOS ICs and through-hole components, making it accessible for individuals with electronic skills to build. It is larger than “Blue2” and operates on a 9V alkaline battery with manual power control through a push-on/push-off button. It lacks automatic turn-off and low battery warning features. Operational Principle: The tester operates by discharging a low-loss polypropylene capacitor, which is charged to 2V, into an inductor approximately five times per second. A functioning inductor or transformer winding will form a resonant circuit that produces a ringing waveform. If short-circuited turns are present, they dampen the resonant circuit, reducing the ringing. Circuit Description: The device uses the same front-end circuit as the “Blue2,” where the waveform is fed into a high-impedance JFET buffer. The waveform is then processed by half of an LM393 dual comparator with hysteresis to generate square waves until the ringing voltage decays to about 30mV peak-to-peak. The resulting square waves are counted by a CD4518B dual decade counter. The counts are displayed using a pair of CD4511B latch/decoder/7-segment driver ICs. An additional feature prevents the counter from resetting incorrectly if it reaches 99. Theoretical Use: The tester is useful for diagnosing faults in inductive components such as transformers and chokes found in electronic equipment like switch mode power supplies, LCD backlight inverters, and older CRT transformers. These components are often expensive and hard to replace, making accurate diagnosis essential. Testing Methodology: The tester is capable of testing both high-frequency types with ferrite cores and low-frequency iron-cored transformers. It outputs a low voltage that usually allows inductive components to be tested in-circuit unless other circuit faults interfere. For definitive results, components should be tested individually. Interpreting Results: High-quality ferrite-cored transformers typically show readings between 50 and 99 rings. A reading below 10 usually indicates shorted turns. However, anomalies like a fully shorted secondary winding could misleadingly show higher readings, such as 37 rings. The effect of partial shorts in primary windings can be tested by inducing shorts in secondary windings, providing a comparative analysis between suspected and known good transformers. Low-frequency transformers typically show lower readings due to the nature of their operation and materials. Recommendations for Use: Bob encourages extensive use of the tester on various transformers and inductors to develop a practical understanding of typical readings, as these can vary widely across different types and models of inductive components.

BLUE K7214+ ESR meter circuit same as K7254, EVB & Dick Smith MKII ESR Meter

NEW Blue K7214+ ESR Meter classic circuit same as Blue ESR Meter, EVB ESR Meter, Dick Smith MKII ESR and Low Ohms Meter with translucent blue case Please note: The picture is just to show the measurement result. The package does not include any batteries. This K7214+ ESR METER is based on the famous BLUE ESR METER classic circuit, using a new low-power MCU to replace the original ZILOG Z86E0412 microprocessor, a new design of firmware, in addition to the original BLUE ESR METER all the functions, you can test hook zeroing data saved to the microcontroller EEPROM, so you do not have to do zeroing operations every time you turn on the computer. You can set the automatic shutdown time of the meter, and the shutdown can indicate the battery voltage, the battery life is much higher than the model using ZILOG Z86E0412 microprocessor. Red ultra-high brightness LED display, measurement results can be displayed more clearly. Note:Blue ESR Meter has been popular since 2007. This is the latest Bob Parker design and successor to the famous Dick Smith MKII ESR and Low Ohms Meter. This handy and cost-effective meter, can measure capacitor equivalent series resistance (ESR) in the circuit. ESR is a very important quality and performance characteristic of capacitors greater than 1uF. This meter makes quality measurements which are usually not possible to check with capacitance meters. For more ESR meter knowledge, you can visit: bobparker.net.au/esr_meter/esrmeter.htm ESR Meter (Mark II) Features * Tests electrolytics in-circuit <100mV test voltage, & test leads are non-polarized * Auto-ranging to cover 0.01 – 99 ohms * Update speed: 4 readings/second * Single push button to easily control all functions * Test lead resistance zeroing compensation is stored in non-volatile memory, You don't have to zero the test leads after every turn on * Automatic power off time adjustable from 1 to 9 minutes (0: clear auto power off) * Low battery voltage warning ('b' flashes on right-hand digit),Displays battery voltage for a few moments before shutdown * Big, easy to read 0.5 inch (13mm) high brightness LED displays * Table of typical good capacitor ESR readings on the front panel

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