Electric Switches>
Preamble
In Circuits with Physical Switches, we showed how switches acting as our variables can create logic gates.
However, we don’t want to use physical switches to control our logic gates. we need voltage-controlled switches — these are transistors: “Electric Switches”
Transistors: the basic building blocks of all computer hardware
Design
- They can either be “open” or “closed” / connected or disconnected
- They have 3 terminals (A, B, C)
- The “Gate” (C) controls the path from point A to point B.
The above shows how when C is “high”, it’s equivalent to having a closed physical switch
and vice versa for when C is low
nMOS and pMOS
There are two types of transistors:
- nMOS transistors: when C = 1, it’s connected!
- pMOS transistors: when C = 0, it’s connected!
- It has the Inversion Bubble on it.
- How are these switches switched?
History
- Made by a bunch of dudes in 1947; won a Nobel prize in physics in 1956. Crazy stuff