The Equotip measuring principle is physically a rather simple, dynamic hardness test.

An impact body with a hard metal test tip is propelled by spring force against the surface of the test piece. Surface deformation takes place when the impact body hits the test surface, which will result in loss of kinetic energy. This energy loss is calculated by velocity measurements.

When the impact body is passing the coil at a precise distance from the surface, a signal voltage is induced during the impact and rebound phase of the test. The voltages are proportional to the velocity.

Signal processing by the electronics provides the hardness reading for display and storage.