1. Homework Statement
Why are the two circuits below equivalent?
The Attempt at a Solution
I am studying BJTs, and in my textbook the equivalent resistance of resistor 1 and 2 is noted to be in parallel. The text provides no explanation why. In my search for an explanation I stumbled upon a video from David Williams (https://goo.gl/VCCuCy) where he redraws the circuit on the left. Once it is in the form on the right I can identify why the resistors are in parallel, but I do not understand how Mr. Williams redrew the circuit.
I would greatly appreciate if someone could walk me through their thought process. For now I can simply remember to do that transformation, but I want to understand the fundamentals so I can apply that technique to different circuits.
If my usage of the terms transformation and equivalent are incorrect for this case please let me know.