Electromagnets use electric current to generate a magnetic field which can be turned on or off as needed. They are made from a softer iron which quickly dissipates the induced magnetism after the current is switched off.  Electromagnetic strength is dependent on a variety of factors, such as the number of coils in the electrical wire that generates the power, the applied current, and the core material’s magnetic permeability. Categories of electromagnets include flat-faced, parallel pole, standard lifting, suspension, laboratory, and permanent.