Spring 2018
Voltage in a Circuit
Find the voltage of an element in a circuit
Learn It!
Pre-Requisite Knowledge
Using the Voltage Divider Concept
Use the Voltage Divider concept to find the voltage drop across one resistor
\( \begin{equation} a. V_{out} = 1.5 \\b. V_{out} = 2V \\c. V_{out} = 3V \\d. V_{out} = 4.5V \\e. V_{out} = 6V \end{equation} \)
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.
What about KVL and Ohm's Law?
\[V_1=V_{total} \frac{R_1}{R_1+R_2}\]
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 \(A\)