CS355 Sylabus

Elementary Digital Circuits

All electrical (including digital electrical circuits) are made with transistors
- Read about the invention of the transitor at PBS: click here
- Transistor 101: click here
Complex digital circuit are designed and constructed using smaller elementary digital circuit which are the basic building blocks (like houses are built with basic material like bricks)

The elementary digital circuit are called gates, they are:

Not gate

See how it works: click here

/home/cs355001/bin/cs355sim /home/cs355001/demo/circuits/not

And gate

See how it works: click here

/home/cs355001/bin/cs355sim /home/cs355001/demo/circuits/and

Or gate

See how it works: click here

/home/cs355001/bin/cs355sim /home/cs355001/demo/circuits/or

Exclusive-Or (Xor) gate

See how it works: click here

/home/cs355001/bin/cs355sim /home/cs355001/demo/circuits/xor

Nand (Not And) gate

See how it works: click here

/home/cs355001/bin/cs355sim /home/cs355001/demo/circuits/nand

Nor (Not Or) gate

See how it works: click here

/home/cs355001/bin/cs355sim /home/cs355001/demo/circuits/nor

Note: all these gates can have more than 2 inputs.
- And-gates with 3 or more inputs: output is 1 only if all inputs are 1, otherwise 0.
  Example of and-gate with 5 inputs: click here
- Or-gates with 3 or more inputs: output is 0 only if all inputs are 0, otherwise output is 0.
  Example of or-gate with 5 inputs: click here
- Xor-gates with 3 or more inputs: output is 1 only if an odd number of inputs are 1, and output is 0 otherwise (even number of inputs are 1)
  Example of xor-gate with 5 inputs: click here
- Nand-gates with 3 or more inputs = a multi-input And-gate followed by a Not-gate
- Nor-gates with 3 or more inputs = a multi-input Or-gate followed by a Not-gate