| description |
|---|
Electricity baby! Down to the basics and physical layer! |
Let's zoom in all the way:
Computers are simply made out of transistor switches.
Transistors are microscopic crystals of silicon that use the electrical properties of silicon to act as switches. Modern computers have what are referred to as field-effect transistors.
Let's visualize 3 different pins.
When an electrical voltage is applied to pin 1, current then flows between pins 2 and 3. However, when voltage is removed from the first pin, current stops flowing between pins 2 and 3.
When we begin to zoom out we notice that there are diodes and capacitors when taken together with the transistor switches, we now have a memory cell.
A memory cell keeps a minimum current flow to which when you put a small voltage on its input pin and a similar voltage on the select pin, a voltage will appear and remain on its output pin. The output pin remains in its set state until the voltage is removed from the input pin in conjunction with the select pin.
- The presence of voltage indicates a 1 in binary and the absence of voltage indicates a 0 in binary
- This is what is meant by ON or OFF