Freebie Friday: How Computers Work: Processor and Main Memory
The picture above shows a 'bottom key' that controls an electromagnet.
The electromagnet, in turn, controls the top key. A key and the electromagnet that controls it are, together, called a relay. The relay is in the dashed box.
When the bottom key is pressed, the electromagnet is powered and the electromagnet becomes magnetic. That makes the electromagnet attract the top key and pull the top key down just like a finger can push a key down. A magnet (or a powered electromagnet) attracts the top key because the top key is made of steel. A magnet (or a powered electromagnet) does not attract the wires because the wires are made of copper.
Important: The electromagnet does not ever touch the top key. No electricity can go from the electromagnet to the wires attached to the top key.
A computer is almost entirely made up of a lot of relays (today, transistors) connected by wires. Just how the relays are connected and just what they do is the main subject of this book. Other concepts, especially programming, will also be explained.
If you read this book and Forest M. Mim III's Getting Started in Electronics, you'll know more about the subject than 99.9 percent of the people on the planet. Link
