A transformer (01) for transmitting data and/or energy, including a concentric coil pair with a fixed first coil (04) and a second coil (05) which is mounted so as to be rotatable with respect to the first coil (04), wherein the coils (04, 05) are arranged with respect to one another in such a way that they are magnetically coupled. The transformer (01)—is defined, in particular, by the fact that the first and the second coils (04, 05) are embodied as printed circuits on one multi-layered circuit board (02, 03) each, wherein in each case a magnetically conductive layer (07) is attached to the outer layers of the multi-layered circuit boards (02, 03), wherein the magnetically conductive layers (07) are selectively connected to one another by recesses which are formed in the circuit boards (02, 03) and filled with magnetically conductive material.
