A new type of a DC plasma source was developed for an improved treatment of extended planar surfaces with plasma based processes under atmospheric pressure. In this paper, the Long Arc Generator ("LARGE") is presented with the focus on its physical principle and on its operation parameters. According to the geometry of the plasma source the emanating plasma jet is up to 450mm broad in the present state of development. It allows a more homogenous and economical treatment of large planar substrates than it was possible with conventional plasma sources. Examples of applications of the LARGE plasma torch are demonstrated with a CVD coating process and a surface activation process, both under atospheric pressure.