Which type of logic is formed by two or more normally open switches in parallel?

The type of logic formed by two or more normally open switches in parallel is NAND logic. In a parallel configuration, the switches can be thought of as allowing the circuit to be completed (or "on") if at least one of the switches is closed. This behavior aligns with NAND logic, which outputs a low signal only when all inputs are high (in this case, all switches closed); otherwise, it outputs a high signal.

When recalling logic gates, the normal behavior of NAND logic is that it produces an output that is the opposite of AND logic. If we consider AND logic, it would require all switches to be closed to provide a high output. In contrast, parallel switches function in such a way that having any one of them closed generates a high output, which is characteristic of the NAND logic behavior when viewed through the lens of its output characteristics being inverted.

Therefore, acknowledging the functionality of switches in parallel clarifies that they exhibit NAND logic properties.