IEC 62047-29:2017(E) specifies a relaxation test method for measuring electromechanical properties of freestanding conductive thin films for micro-electromechanical systems (MEMS) under controlled strain and room temperature. Freestanding thin films of conductive materials are extensively utilized in MEMS, opto-electronics, and flexible/wearable electronics products. Freestanding thin films in the products experience external and internal stresses which could be relaxed even under room temperature during a period of operation, and this relaxation leads to time-dependent variation of electrical performances of the products. This test method is valid for isotropic, homogeneous, and linearly viscoelastic materials.