The Amateur Electrical Engineer

By Perry Henderson

We all hear the word utilized many times a day in different context, but many of us have no idea as to what it means from a physics or electrical engineering perspective. Power is simply the rate at which electrical energy is transported in an electrical circuit. From a mathematical formula standpoint, power is P = VI. This equation is Power (P) equals voltage (V) times current (I). Power is measured in what are called Watts. The power equation is as common in electrical engineering as Ohm’s Law is. From the design of electronic circuits to the design of grids for cities or new airports, power as a concept is essential for the design of systems that meet the requirements of the system stakeholders.

If you remember direct current (DC) (which is current that does not change directions, in the most simplistic way to explain) the manipulation of the formula for calculations for power is relatively easy. As we have stated in previous post, the current and voltage remain at a constant, so this allows the electrical practitioner to easily calculate the rate of consumption of power for electrical components such as LEDs and resistors. Even more complex components such as microcontrollers can be understood to a very high degree of confidence with the proper yet simple calculation utilizing the power equation. One thing that occurs due to the laws of physics that are important for the amateur electrical engineer to have at least a decent grasp over, is heat that occurs and is corelated with power loss. Electronic and electrical systems while generating the ability to power technology, produce heat that must be accounted for.

The dynamic cousin of DC is AC or alternating current. Alternating current switches back and forth or reverses its direction periodically (this is once again a highly simplified way of looking at this). AC is excellent for getting electricity to go longer distances. Remember in our earlier work that in Europe AC is 50hz and in the USA it is 60hz. When it comes to AC and power it becomes a bit more complicated than with DC. There exist what are called phase differences, and this makes the ability to calculate power more difficult for the electrical professional. Concepts that are more complex electrical engineering concepts such as reactive, real, and apparent power become significant. Engineers that design more complex electrical engineering systems must understand these aspects of power as it relates to AC applications such as motors and other industrial based technologies.

For the electrical engineer at the professional level or the amateur electrical engineer level, power is everything. There is no electrical based technology that does not need it. Applications from satellites, rockets, calculators and the very device that you may be reading this post on depend on the relationship between voltage and current. My advice to you is to master these basic equations no matter how simple they may appear. It is the basics that make the master. P=IV, so simple yet so complex. Study away !!

© Copyright 2025 Perry Henderson