a linear circuit - independent sources, linear dependent sources, linear elements Linearity theorem: The response is proportional to the source or that multiplication of all independent source voltages and currents by a constant k increases all the current and voltage responses by the same factor k(including the dependent source voltage or current outputs).A linear circuit -- independent sources; linear dependent sources; linear elements. The response is proportional to the source or that multiplication of all independent source voltages and currents by a constant k increases all the current and voltage responses by the same factor k (including the dependent source voltage or current outputs). Linearity theorem: