# Kirchhoff Voltage Law in a two port network

In a tutorial about h parameters of a two port network, I find the below snippet in the image unable to grasp. According to KVL, the total voltage in a loop is the algebraic sum of the individual voltages. But why in this tutorial ( equation 1 in below image ) it's given so. It should be something like V1 = h11 I1 + V2 according to KVL. What is this h12 V2 mean?

The whole tutorial is here. https://www.electrical4u.com/hybrid-parameters-or-h-parameters/

the total voltage in a loop is the algebraic sum of the individual voltages.

This is KVL, not KCL.

It should be something like V1 = h11 I1 + V2 according to KCL.

The voltage across the resistor is $$\h_{11}I_1\$$ and the voltage across the controlled voltage source is $$\h_{12}V_2\$$.

Therefore the KVL equation for this subcircuit is

$$V_1 = h_{11}I_1 + h_{12}V_2$$

as shown in the quoted text.

What is this h12 V2 mean?

$$\h_{12}V_2\$$ is the voltage across the VCVS shown in the diagram.

$$\h_{12}\$$ is the gain of the VCVS.

$$\V_2\$$ is the voltage across the other port of the 2-port. This is shown in the very next diagram in the linked tutorial.

• I made some mistakes in my actual question. Now I have edited the question. Can you tell me how the equation 1 represents the circuit diagram? How did the author conclude that KVL applicable there? – Praveen Kumar P S May 25 '19 at 17:17
• Why do you think KVL wouldn't be applicable? So long as we don't violate the lumped circuit approximation, KVL can be applied to any path we like around a network. – The Photon May 25 '19 at 18:13