C N )||( | | | | P
E )||( +-->|-+--)---+--|(--+-o U
)||( | | | GND T
o----)||(--+--|<----+----------+

A power supply consisting of a full wave rectifier circuit
feeding a capacitor input filter circuit

And here are some very silly examples:
|\/\/\/| ____/| ___ |\_/| ___
| | \ o.O| ACK! / \_ |` '| _/ \
| | =(_)= THPHTH! / \/ \/ \
| (o)(o) U / \
C _) (__) \/\/\/\ _____ /\/\/\/
| ,___| (oo) \/ \/
| / \/-------\ U (__)
/____\ || | \ /---V `v'- oo )
/ \ ||---W|| * * |--| || |`. |_/\

//-o-\\
____---=======---____
====___\ /.. ..\ /___==== Klingons rule OK!
// ---\__O__/--- \\
\_\ /_/

There is an important subgenre of ASCII art that puns on the standard
character names in the fashion of a rebus.
+--------------------------------------------------------+
| ^^^^^^^^^^^^ |
| ^^^^^^^^^^^ ^^^^^^^^^ |