A breadboard (usually) consists of a set of two power rails on either side, often colored red and blue for positive voltage and ground respectively, which each run the whole length of the board. Every hole along a rail is connected. (Note that larger breadboards often have a break in these rails in the middle of the board.)
Inside the rails there are two columns of connected rows, separated in the middle by a small gap. Each row contains five connected holes. The center slot separating the columns is sized so that a dual in-line packageintegrated circuit can be mounted in the center of the breadboard.
Press the button to highlight the breadboard's internal connections:
