Ohm’s Law: Basics and Applications

By Perry Henderson

Georg Simon Ohm is credited with the realization and development of Ohm’s Law. The law is a basic principle that any electrical professional must know and understand. Ohm first came across and developed the law in the early 19^th century. The power of the law is in its ability to analyze circuits and their behavior. The law, while relatively simple, has profound applications and implications for electrical theory and technological applications.

Ohm’s law is a relatively simple equation. The law is V = IR. In this equation V is voltage. I is current, and R is resistance. V is measured in volts, I is measured in current, and R is measured in Ohm’s. If we were to translate this equation into English, it would read: voltage is equal to current times resistance. The wonderful thing about the algebraic expression of this equation is that if two variables are known, it is easy to figure out the third.

Electrical engineers and electronics technicians know that to properly troubleshoot and study a circuit a sound understanding of Ohm’s Law is needed. If one knows the voltage from a battery and the resistance provided by a resistor, (a type of electronic component), then the amount of flowing current can be known by calculation. The knowledge provided by the law aids in the design and integration of components into simple or complex circuits and electronics.

Ohm’s law does have some limitations and stipulations in its applications. One of those limitations is that it applies to ohmic materials. These ohmic materials are materials where there is a stable level of resistance throughout the material no matter the number of amps. Two components that Ohm’s Law does not apply to in the typical sense are transistors and diodes. In these two common components of electronics, voltage and current can change depending on many different variables present in the circuit.

The primary step in the journey of becoming a professional electrical engineer or an amateur electrical engineer is taking the time to master the equation known as Ohm’s Law. With a strong understanding of Ohm’s Law, systems of complexity can be modeled to a high degree of precision. Ohm’s Law also lays the foundation for more advanced laws that we will encounter such as Kirchoff’s Laws. From day one an electrical professional with a solid grasp of Ohm’s Law has a strong base to proceed with confidence in their study of electrical engineering.

The Amateur Electrical Engineer