Which attribute will impact power usage on an IoT device?

• A. Sensor resolution
• B. Number of attached sensors
• C. Clock rate of the CPU
• D. Supply voltage

Answer: (D)

Power usage in IoT devices is most directly tied to the supply voltage because energy drawn equals voltage times current, and the switching energy in digital electronics grows strongly with voltage. In CMOS logic, the dynamic power consumed during operations scales roughly with the square of the supply voltage (and with how often the circuit switches). That means lowering the supply voltage reduces energy per operation and, since all parts—CPU, radios, sensors—draw from the same supply, it has a broad and predictable impact on total power.

The other factors can affect power, but their effects are more situational. More sensors or higher sensor resolution can increase power when they’re actively sampling or transmitting, and increasing the CPU clock rate boosts switching activity, but these depend on usage patterns. The voltage change, however, directly alters the energy cost of every operation across the device, making it the most impactful leg on power consumption.