[en] In our investigations of interaction between electromagnetic field and matter experimental results were observed, which were grouped under the working name “Surface Photo Charge Effect” (SPCE). The important point is that the interaction of any solid with electromagnetic field induces an alternating electric signal with the same frequency as the frequency of the incident field [1]. The voltage between the irradiated sample and a second solid, whose potential is assumed to be zero, is measured contactlessly. The SPCE represents generation of an alternating voltage when a solid interacts with a modulated electromagnetic field. The potential difference between the irradiated sample and the common ground of the system is measurable and depends on many factors. The name Surface photo charge effect has been kept historically. It does not reflect the newer experimental results. (author)