* Fixed-Potential PEC Objects with a Nonzero Voltage
* '''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.* Wire '''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.* Volume '''Wire Currents'''* '''Permanent Magnets'''
[[Image:Static1.png|thumb|330px| EM.Ferma's PEC dialog.]] === Using Fixed-Potential PEC Objects as Voltage Sources ===
Under the static condition, every point on a PEC object has the same electric potential. By default, this is a zero potential, meaning the PEC object is "grounded". In EM.Ferma, a PEC group has a ''Fixed Potential''' property, which is expressed in Volts and has a zero default value. If you define a new PEC group and keep its default zero voltage, the objects belonging to that group will simply act as metal objects of your physical structure. However, you can define a nonzero voltage value for a PEC group. You can do in the property dialog of the PEC group, which you can access by right-clicking on the group's name in the navigation tree and selecting '''Properties...''' from the contextual menu. In the case of a nonzero voltage, all the PEC objects belonging to that group effectively turn into voltage sources. For example, two parallel PEC plates, one with a zero potential and the other with a nonzero potential represent a simple air-filled capacitor. Note that the voltage value can be positive or negative.
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<table>
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<td> [[Image:Static1.png|thumb|330px| EM.Ferma's PEC dialog.]] </td>
<td> [[Image:Static2.png|thumb|330px| EM.Ferma's Dielectric/Magnetic Material dialog.]] </td>
</tr>
</table>
=== Volume Charge Sources ===
To add a new volume current source group to a project, right-click on "Volume Currents" on the Navigation Tree, and select "Insert New Current Source..." From the Volume Current Source Dialog, you can change the default brown color of the source group or set the values of the Current Density magnitude and unit direction vector components. The default direction vector is z-directed.
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<td> [[Image:Static3.png|thumb|330px| EM.Ferma's Charge Source dialog.]] </td>
<td> [[Image:Static5.png|thumb|330px| EM.Ferma's Volume Current Source dialog.]] </td>
</tr>
</table>
=== Wire Current Sources ===