Which logical function requires all inputs to be active or contacts to be closed to energize the load?

The function that requires all inputs to be active or contacts to be closed to energize the load is the AND function. In an AND logic operation, the output is true (or the load is energized) only when all of the inputs are true (active). This means that if any single input is not active or any contact is open, the output will remain false, and the load will not be energized.

In practical applications, you can think of this as a circuit where multiple switches (inputs) must all be closed for the light (load) to turn on. This characteristic makes the AND function essential for scenarios requiring collective action from multiple conditions.

Other logical functions behave differently: for instance, the OR function will energize the load if at least one input is active, while NAND and NOR functions will yield different results based on a combination of active and inactive inputs, leading to energizing the load under different conditions.