How does an Atari cartridge work?

A ROM (Read Only Memory) chip contains a set of instructions and data which make up the game.

Power is supplied to the cartridge, and the data lines from the cartridge are "read" from and "written" to by the console.

Based on the signals on the data lines, the console changes what it is displaying on the screen, and what audio signals it is generating.

Look at another section of how an Atari 2600 works:

• Atari 2600 console - processes controller input and cartridge instructions to create video and audio which are output to the TV
• Atari power cable - takes household current (120 Volts, 50-60Hz AC in the US) and transforms it into 9 Volt DC, roughly equivalent to a 9 Volt battery.
• Controllers (joysticks, paddles, keyboard controllers, etc...) - Transform human movement into signals the console can understand.
• RF cable and switch box - Sends the signal from the console to the TV's tuner as if it were a broadcast channel
• Television - The only way to see and hear what the console is producing