Abstract: A current source module for joining methods with current-generated heat support that includes a base body formed monolithically as a single component, having a first immovable attachment element for connecting a first joining tool and at least one formed first receiving space. In the first receiving space, a control element is disposed including a linearly movable second attachment element for connecting to a second joining tool, and in the first or additional receiving space a transformer unit for electrical supply is disposed. Furthermore, a welding gun is provided that includes such current source module, and a first joining tool formed as an immovable electrode arm, and a second joining tool formed as a movable electrode arm, wherein the immovable arm is connected to the first attachment element and the movable arm is connected to the second linearly movable attachment element, wherein the electrode arms include electrodes connected to the transformer.