Basic Voltage Divider
Fall 2018
Voltage in a Circuit
Find the voltage of an element in a circuit
Learn It!
Pre-Requisite Knowledge
Goal
Using the Voltage Divider Concept
Use the Voltage Divider concept to find the voltage drop across one resistor
$$$a. V_{out} = 1.5 \\b. V_{out} = 2V \\c. V_{out} = 3V \\d. V_{out} = 4.5V \\e. V_{out} = 6V$$$
Part 1
Using the Voltage Divider Rule
We want to find the voltage across the $1 \Omega$ resistor, which has been named $V_{out}$
We recognize this as a special structure, called a voltage divider. If we want the voltage across one resistor that is in series with another, the voltage divider concept will likely be useful to us.
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What about KVL and Ohm's Law?
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Proof
$V_1=V_{total} \frac{R_1}{R_1+R_2}$
This is the Voltage Divider Rule (VDR).

The voltages across resistors in series have a this very special relationship.
$V_{out}= 6\frac{1}{3+1}$
With the VDR, we're on the home stretch.
$V_{out} = 6/4 = 1.5$
Final Answer is $A$