NEIEP Mechanics Practice Exam

What does the acronym DPDTNO stand for in terms of switch designation?

1. Double Pole-Dual Throw-Normal Open

2. Double Pole-Double Throw-Normal Open

3. Dual Pole-Dual Throw-Normal Open

4. Double Point-Double Throw-Normal Open

The correct answer is: Double Pole-Double Throw-Normal Open

The acronym DPDTNO stands for Double Pole-Double Throw-Normal Open. This designation describes a type of switch that has two separate circuits (hence "Double Pole") and can connect each of these circuits to one of two outputs (indicated by "Double Throw"). The term "Normal Open" indicates that in its default, unactivated state, the switch does not complete the circuit for the load; it only connects when manually operated or actuated. This switch design is widely used in various applications requiring reliable circuit control, allowing for the switching between multiple circuits or configurations. The "Double Pole" feature is significant because it means that both circuits can be controlled simultaneously, providing more complex wiring configurations and operational versatility. Other terms in the incorrect options do not accurately reflect the standard nomenclature used in electrical wiring, as "Dual" and "Double Point" do not represent recognized classifications in switch designations. Therefore, the understanding of the term "Double Pole-Double Throw-Normal Open" is crucial for correctly identifying and utilizing this type of switch in electrical systems.