Printed circuit boards may look scary at first but they’re actually fairly simple to understand with breadboards.
Let’s look at some examples of logic gates. Logic gates connect an electric path where a current can flow and can’t flow.
In the picture below is an AND gate where one button AND another button must be pressed at the same time to allow electric flow.
An OR gate works similarly except only one button press is required to allow electrical flow to pass. In all circuits electrical flow will always travel the shortest distance to get to it’s destination ignoring other paths. When the current reaches the first switch it will be unable to cross therefore it will travel the longer distance around the circuit, if the switch is pressed then the electrical flow will continue down the path until it reaches it’s destination.
Switches on a breadboard work in an interesting way. While a switch is not pressed electrical flow can still pass across freely in a linear path. When a switch is pressed it acts like a railroad track, it changes paths to the opposite side.
As you can see there are two different ways to use a switch and get a similar result.