two solenoids with helical copper wire wound on black coil on white background

background black circuit closeup coil component conductor copper core current cylinder cylindrical design detail development device disposal electric electrical electromagnet electromagnetic electronic electrotechnics electrotechnology element energy engineering equipment ewaste ferrite ferromagnetic field helical helix inductance induction inductor industrial industry isolated long macro magnetic material mechanical network nobody nopeople object part recycle recycling repair replace science service shape shop single solenoid spare spiral store supply technical technology two voltage waste white whole winding wire wrapped