Understanding Kirchhoff's Voltage Law in Simple Circuits

[ravenprp]

I have a simple question regarding my PPT notes for class, it's not a homework question.

Each of the two circuits in the image.. the voltage across the two terminals coming out of the external circuit also appears across the a and b terminals on the right... why is that?

 

[antonantal]

Because there is no resistance between the terminals of the external circuit and the a/b terminals, and consequently no voltage drop.

 

[piercas]

This is because the voltage across the external circuit is equal to the voltage across any two points in the circuit, including the a and b terminals. This is known as Kirchhoff's voltage law, which states that the sum of all voltage drops in a closed loop is equal to the sum of all voltage rises. In this case, the voltage drop across the external circuit is equal to the voltage rise across the a and b terminals, resulting in the same voltage being present across both points. This principle is fundamental in understanding the behavior of circuits and is essential to accurately analyze and design them.