Part 01 of 12
From electricity to information
Begin with the physical signal, and discover why a simple yes/no distinction changes everything.
The story before the details
Imagine a machine with no operating system, screen, keyboard, or even a concept of the number seven. All it has is a way to distinguish physical states. That is enough of a starting point. A circuit can receive a high or low signal, combine signals according to fixed relationships, and preserve a state when the right storage structure is present. Meaning is something we assign to those states.
Real electronics are analog underneath our digital descriptions. A voltage might take many values; a logical receiver treats valid ranges as low or high. That is a deliberate abstraction. You should not think of each bit as a tiny bucket containing a literal printed zero or one. It is a persistent or transient physical condition that other circuitry can distinguish.
The fascinating step is composition. A single switch does little. A set of switches can represent a code. A gate can transform that code. A feedback circuit can remember it. A collection of circuits can carry out operations selected by other codes. The end goal is not to memorize device names, but to see how one layer gives the next layer a reliable contract.
What you will discover
These six lessons are arranged so each one answers a question created by the previous one. Do not rush to the last lesson. If a concept feels opaque, use the checkpoint before continuing.
- 01.01What a computer actually is↗Why can a machine follow instructions?
- 01.02Voltage is not literally a one↗How does electricity become a bit?
- 01.03Noise and reliable decisions↗Why only two states?
- 01.04Transistors as controlled switches↗What makes a circuit controllable?
- 01.05Bits, bytes, and meaning↗When does a bit become information?
- 01.06The abstraction ladder↗How can trillions of tiny events seem simple?
Begin with the physical signal, and discover why a simple yes/no distinction changes everything. You should be able to explain each concept using only an input, a rule, an output, and any state that must be retained.