Circuitry, Logic elements (What is an open collector (drain))?

Question

Circuit design

What is an open collector (sink)

Answer 1

I'll try. draw in ASCII
----*--oVcc
|
R
|
*------*----+
| | |
/ / /
| | |
----*------*----*---o GND
Transistors instead of contacts.
PS: What is the question, is the answer. I think during this time it was already possible to "ask" any search engine.