automotive Coating Thickness Gauge WH-82 with LCD screen

Principle

The device uses magnetic thickness measurement method, which non-destructively measures thickness of non-magnetic coating (such as: aluminum, chromium, copper, enamel, rubber, paint, etc.) on magnetic metal substrates (such as steel, iron, alloy and hard magnetic steel, etc.).
Magnetic Method (F-type probe): When the probe contacts the cover layer, the probe and magnetic substrate forms a closed magnetic circuit; Due to the presence of non-magnetic coating, magnetic resistance changes. The thickness of the cover layer can be derived by measuring the change.
Eddy Current Method (NF-type probe): When the probe contacts the cover layer, the probe and non-magnetic substrate forms Eddy Current and gives feedback to the coil inside the probe. 
The thickness of the cover layer can be derived by measuring the feedback.