"current is applied" is correct and usable in written English.
You can use it in a variety of contexts. For example, "A current is applied to the wires to test for continuity."
When an electrical current is applied, the flaps become oppositely charged and bend inward.
The device will start to conduct if a suitable amount of gate current is applied, but otherwise it will not.
An electrical current is applied to darken the gel, allowing passengers to choose from five transparency settings.
Typically not more than 2mA of current is applied at the scalp electrodes to achieve such an E field amplitude.
The solenoid lowers its core when no current is applied, allowing the electromagnet to make contact with the chess piece.
When the current is applied to the electromagnet, the chess piece is attracted to it and sticks.
When the car rolls over a pothole, high-voltage direct current is applied to the coils, extending the armature shaft to keep the car level.
The tablet is held onto the keyboard by a very fancy "memory wire" locking mechanism, which changes shape when a current is applied across it.
When an electric current is applied, the bacteria co-migrate with water to the cathode.
The lightning strike electric current is applied directly to a fastener.
When a cyclic alternating current is applied to the material, the copper separates from the surface region, giving the nanoparticles a platinum-rich outer layer.
