Coils are used in a wide range of applications e.g. transformer, motor, generator, ignition coil for cars and motorcycles, relay, electromagnet, filter and various inductors, nearly all the electronic and electrical products have to use coils. However, coils do not have a complete automatic manufacturing process like standard electronic components, and the existing enameled wires are neither fault-free during production nor ensure 100% quality guarantee. 7700 is a 2 channels, 5000V impulse winding tester that provides the comparison of waveform functions e.g. Area under curve ratio, Area size ratio, Voltage time difference, and you can use the cursor to select desired comparison range to cover all the waveform differences created by electrical properties then detect a faulty component. This model offers various harmonics mode and accommodate all kinds of coils, and become the best tester that you are able to find on the market to certify coil quality.