Additional Resources > Windchill Risk and Reliability Practitioner’s Guide > Fault Tree Analysis > Events and Gates > NAND Gate
NAND Gate
The NAND gate functions like a combination of an AND gate and a NOT gate. The NAND gate is used to indicate that the output occurs when at least one of the input events is absent. The output of a NAND gate can be the top event or an intermediate event. The input events can be basic events, intermediate events or a combination of both. The presence of a NAND gate may give rise to non-coherent trees, where the non-occurrence of an event causes the top event to occur.
Logic Summary
If there is at least one false (F) event, the output is true (T). Table 5-8 shows the input and output events for a NAND gate.
Table 5-8. Truth Table for NAND Gate
Input A
Input B
Output
T
T
F
T
F
T
F
T
T
F
F
T