Abstract: In the case of the current transformer according to the invention, the components used are arranged in a novel manner. The primary winding (7) is arranged around the secondary winding (8), with an extended core (9), at a distance which is provided for the insertion of high-voltage insulation (10). The secondary winding (8) and core (9) are located in an earthed, electrically conductive tube (12) in which the output leads of the secondary winding are connected to earth. This construction results in the avoidance of the core and windings looping around one another, which is necessary according to the prior art, is unfavourable for some applications, and is costly in manufacture.