The equatorial electrojet can be modeled as a quasi-linear concentration of electrical currents flowing along the geomagnetic equator in the E layer of the ionosphere (on the dayside) and closing in a diffuse manner. In the conducting earth, two induction mechanisms may be associated with the electrojet: (1) disturbance variations D, corresponding to time fluctuations in the intensity of the electrojet currents (these have time constants of the order of a few tens of minutes: in this case as a first approximation the current system can be regarded as being fixed with respect to the earth), and (2) the daily regular variation SB, due to the rotation of the earth inside the current system, which is fixed with respect to the sun (in this case, again as a first approximation, the intensity of the electrojet currents can be regarded as being constant). Mayalud and Fambitakoye have experimentally shown that near local noon the part of SR due to the electrojet, SRE, has no measurable induced effect, whereas the D variations have a large one. These conclusions contradict what is generally accepted. We show in a rigorous way that they are true. The proof is based on computations performed for simpe earth models of conductivity, first in the plane approximation for earth geometry and then in the spherical case.