EM.Ferma also offers the following types of source objects for excitation of your physical structure:
* '''[[#Using_Fixed-Potential_PEC_Objects_as_Voltage_Sources | Fixed-Potential PEC Objects]]'''
* '''Volume Charges''': For volume charge sources you need to specify a positive or negative charge density in C/m<sup>3</sup>. You can draw all kinds of solid CAD object under this group.
* '''Volume Currents''': For volume current sources you need to specify a current density in A/m<sup>2</sup>. You can draw all kinds of solid CAD object under this group. Note that current density is a vectorial quantity and has a magnitude and a unit direction vector.