**The Free On-line Dictionary of Computing (30 December 2018):**

digital electronics
The implementation of two-valued logic using
electronic logic gates such as and gates, or gates and
flip-flops. In such circuits the logical values true and
false are represented by two different voltages, e.g. 0V for
false and +5V for true. Similarly, numbers are normally
represented in binary using two different voltages to
represented zero and one.
Digital electronics contrasts with analogue electronics
which represents continuously varying quantities like sound
pressure using continuously varying voltages.
Digital electronics is the foundation of modern computers and
digital communications. Massively complex digital logic
circuits with millions of gates can now be built onto a single
integrated circuit such as a microprocessor and these
circuits can perform millions of operations per second.
(2006-01-14)