# Circuitry problem solving

##### Intros
###### Lessons
1. Introduction to Circuitry Problem Solving:
2. A crash course review on electric circuits.
3. Concept 1: How are individual resistances related to voltage drops?
4. Concept 2: What can we conclude about resistors in series?
5. Concept 3: What can we conclude about resistors in parallel?
6. Concept 4: How can we determine the brightness of a lightbulb?
##### Examples
###### Lessons
1. Problem Solving for Resistors and Voltage Drops
The two circuits below are configured as shown. Circuit B includes an additional resistor R3 placed in parallel with R1. Compare the values of VR1 and VR2 in circuit $B$ compared to circuit $A$ (no change, decrease, increase)?

1. Problem Solving for Lightbulb Brightness with Switches
Two identical circuits are shown below, except Circuit A has an open switch and Circuit B has a closed switch. How does each lightbulb ($R_{1}, R_{2}, R_{3}, R_{4}$ and $R_{5}$) change in brightness compared to when the switch was open? (same, dimmer, or brighter)

1. Problem Solving for Complex Circuit with Missing Values

1. Find the value of the resistor R4.
2. Find the voltage (potential difference) of the battery.
3. Explain how to add one more resistor to make R1 brighter and dimmer.
2. Solving for Lightbulbs and Terminal Voltage
The circuit is connected to three identical lightbulbs:

1. Find the value of the internal resistance.
2. Explain whether each lightbulb becomes brighter, dimmer, or the same after opening the switch.
3. Will the terminal voltage after opening the switch be: greater than, the same as, or less than before opening the switch?