The input and output resistances and , as well as the voltage gain of a two-port network can be obtained experimentally. First, connect an ideal voltage source (a new battary with very low internal resistance) in series with a resistor , and then connect load of two different resistances to the output port. Now the three parameters can be derived from the known values of , and the two measurements of the load voltage , corresponding to the two resistance values used.

Assume , , and the input voltage is measured to be ; also, assume the two different load resistors used are and respectively, with the two corresponding output voltage and . Find , and .

Solution:

First consider the voltage of the input port:

Solving this equation for , we get

Next consider the voltage of the output port:

i.e.,

Using the values of and of the two experiments, we get

Solving these two equations we get

But we know , we get .