Analog v/s Digital Circuits

Analog

• All physical quantities are analog.
• Analog means that the quantity can take any value between its minimum value and maximum value.
• Example :
  i) Temperature, can take any value[-1,12.8,25.002,... etc.].
  ii) Sine waves are analog.

Digital

• Digital means that the quantity can take specific levels of values with specific offset between each other.
• Example :
  i) English alpha consists of 26 letter, there is no letter between A and B.
  ii) Square waves are Digital.

References

• Analog v/s Digital