No there are no circumpolar constellations on the equator.

There's no answer to this question, because the definition of circumpolar depends on where you are. If you're at the pole, all the constellations you can see are circumpolar. If you're on the equator, there are no circumpolar constellations.

A circumpolar current is a type of current that can be found in the Antarctic region. A circumpolar current moves in a clockwise rotation.

"Circumpolar" means it is always above the horizon.

gemini is not circumpolar. the circumpolar constellations for the northern hemisphere are Cassiopeia. Ursa Minor, Draco, Cepheus, and Ursa Major.