Direct current (DC) does not produce a constant electromagnetic field in the conventional sense. A constant or steady current flowing through a wire will generate a static magnetic field around the wire, but it does not produce a continuously varying electromagnetic field.
In the case of DC, the electric current flows in one direction with a constant magnitude. This steady current creates a static magnetic field that circulates around the conductor according to Ampere's law. The strength of the magnetic field is proportional to the current magnitude and decreases with distance from the wire.
Unlike AC (alternating current), where the flow of current periodically changes direction, DC lacks the time-varying component necessary to generate a time-varying magnetic field. In electromagnetic waves, such as those produced by AC, the electric and magnetic fields continuously oscillate and propagate through space.
However, it's important to note that even in the case of DC, there may be some electromagnetic effects associated with the creation or disruption of the current flow. For example, when a DC circuit is switched on or off, there can be transient effects that produce a time-varying electromagnetic field during the switching process. But once the steady current is established, the electromagnetic field associated with DC becomes relatively static.