This document covers the basics of PCB design with a focus on how ideal circuit elements behave. You'll also learn the fundamentals of PCB design which you'll later apply in the project section of this week’s training.
In this section, we will first cover the fundamental mathematical equations that are necessary in designing and analyzing any circuit.
Ohm's law tells us the relationship between voltage, current, and resistance in a circuit,
$$ \large V = I \cdot R $$
Where voltage $V$ is the difference in potential between two points in volts, current $I$ is the flow of electrical charge through those points in amperes, and $R$ is the resistance of the material or element in Ohms ($\Omega$).
The next equation is KCL, which is short for Kirchoff's Current Law. KCL states that the sum of all currents entering a node must equal the sum of all currents leaving that node.
$$ \large I_{entering} = I_{leaving} $$
This has the added implication that all components in series have the same amount of current flowing through them.
Next, Kirchoff's Voltage Law (KVL) tells us that in any closed loop, the total voltage gained minus the total voltage lost is equal to zero.
$$ \large V_{gained} = V_{lost} $$
For example, when tracing this loop counterclockwise, you gain 12V across the battery, meaning that you must lose 12V across the resistor to get back to 0V.
If any of these concepts are confusing for you, please take the time to review the following videos to get familiar with them. These are fundamental concepts you need to design even the most basic circuits.