NOR gate
OR followed by NOT: the output is 1 only when every input is 0.
Truth table
| A | B | Y |
|---|---|---|
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 1 | 0 | 0 |
| 1 | 1 | 0 |
Pins
2–8 inputs on the left, one output on the right (the bubble means inverted).
How to use it
Also a universal gate — Norro is named after it. Two cross-coupled NORs remember one bit: the simplest memory circuit.
Usage example
OR, then inverted: the output is 1 only when both inputs are 0 (both are off here, so the LED is lit).