%0 Journal Article
	%A Alexandr A. Penin
	%D 2009
	%J International Journal of Electronics and Communication Engineering
	%B World Academy of Science, Engineering and Technology
	%I Open Science Index 28, 2009
	%T The Invariant Properties of Two-Port Circuits
	%U https://publications.waset.org/pdf/5517
	%V 28
	%X Application of projective geometry to the theory of two-ports and cascade circuits with a load change is considered. The equations linking the input and output of a two-port are interpreted as projective transformations which have the invariant as a cross-ratio of four points. This invariant has place for all regime parameters in all parts of a cascade circuit. This approach allows justifying the definition of a regime and its change, to calculate a circuit without explicitly finding the aparameters, to transmit accurately an analogue signal through the unstable two-port.

	%P 878 - 884