Oklahoma Electrical Practice Exam

What advantage does a 24v device have over a 12v device?

1. It offers better efficiency

2. It has a lower current draw

3. It requires less maintenance

4. It is smaller in size

The correct answer is: It has a lower current draw

A 24v device provides a significant advantage in terms of lower current draw compared to a 12v device. The relationship between voltage and current is governed by Ohm's Law, which states that the current (I) is equal to the voltage (V) divided by the resistance (R) in a circuit (I = V/R). When using a higher voltage, such as 24v, for the same power requirement (measured in watts), the current drawn by the device is reduced. This is particularly beneficial in reducing the overall amount of heat generated in the conductors and the device itself, which can enhance reliability and longevity. Moreover, lower current draw can lead to smaller gauge wiring being used, which can reduce material costs and installation complexity. This advantage is a key reason why many systems, especially in larger installations or where efficiency is critical, opt for higher voltage systems. While the other options might suggest benefits that could be applicable in certain contexts, they do not directly relate to the fundamental electrical principles explaining the efficiency and practicality of using a higher voltage system. For instance, while a higher voltage can lead to improved efficiency in certain scenarios by reducing losses, the most straightforward and universally applicable advantage of a 24v device is