Connecting two NC limit switches in parallel to control two cylinders is called ______ logic.

• A. AND
• B. NOR
• C. NAND
• D. OR

Answer: (C)

When two normally closed switches are wired in parallel, the circuit conducts as long as at least one switch is in its closed (idle) state. A NC switch is closed until it’s actuated, so with parallel paths, current can flow if either switch is not yet pressed. Only when both switches are actuated and opened is the path broken. That behavior corresponds to a NAND function: the output is true unless both inputs (the actuation states) are true. So this parallel NC setup implements NAND logic for controlling the two cylinders. If only one switch is actuated, the other keeps the circuit alive; only when both are actuated does the output turn off.