Circuits and Electronics Midway in Chapter 2 Resistor Combinations

Quick review Ohm’s Law: V = I R KVL :  v = 0 All Voltages in a Loop sum to Zero KCL :  i = 0 All currents in a Node sum to Zero

Resistors in a Loop Lets’s say you have a loop with one voltage source and two resistors: The voltage drop on the first resistor will be IR 1 and the voltage drop on the second resistor will be IR 2 The total voltage Vt = IR 1 + IR 2 Factor Vt = I [R 1 + R 2 ]

Results The Total of the Resistors in a loop, or in SERIES will be: Rt = R1 + R2 + R3 + R4 + ……. Therefore, the Current, I = Vt /[R1 + R2] Even farther, the total voltage, Vt, will divide over the two resistors

Now, lets look at the NODE Let’s say you have three circuit branches coming into a node, and their other terminal ends at the same other node. One has a current source, and the other two branches are resistors. The voltage on each branch will be EQUAL. The total current I = V\[R1 + R2 + R3 + …]

Results The Resistances add in a loop - SERIES The resistance inverse add in a node: Parallel configuration Even more, the division of voltage and current is proportional EXAMPLE PROBLEMS in our book are problems 2-13, 2-14, 2-15