The Laws of Circuit - you can learn and practice by just reading

Copyright. Charles Kim 2006

How the Elements are connected - Dummy bare wire
Do you have a problem in recognizing series or parallel resistors in a circuit? You have no problem finding that R1 and R2 are in parallel in the figure (left),
but you hesitate a little finding R1 and R2 in parallel in the figure (right)?
You can easily recognize two Delta shapes in the figure left, but do you have problem in the figure right? Even though two are exactly the same circuit.
The point is not to focus on the shape of a circuit, but the connectivity of the elements in the circuit. In other words, how an element or several elements are connected to a node. What/how elements are connected to a node is important to recognize their connections in the circuit. Labeling nodes is always helpful. Tracing elements following nodes is very important. I wonder, now then, you can convert the circuit in the left to the circuit in the right.



Note: R6 are between the nodes of (c,e) and (d, f). R2 is between (a) and (c,e). Similarly, R5 is between (b) and (d, f). Now we can easily see from the figure right that R1 and R6 are in parallel!