Hello. Please look at the attached image first. There are two circuits A and B which have individual electrical components a and b. Components a and b are electrically and directly connected by the red lines. Impedances of individual components a and b are not matched, however, equivalent impedances of circuits A and B are matched. Now a signal travels from A to B. Then, is there a signal reflection due to impedance mismatching? Which impedances are important for the signal? Impedances of individual components at the ends of the connection or equivalent circuit impedances? Please help to clarify my confusion. I need to know to understand an impedance matching network.