Welcome to our exploration of Ohm's Law, one of the fundamental principles in electrical engineering. Ohm's Law describes the relationship between three key electrical quantities: voltage, current, and resistance. The law states that the current flowing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance.
The mathematical expression of Ohm's Law is V equals I times R, where V represents voltage measured in volts, I represents current measured in amperes, and R represents resistance measured in ohms. This formula can be rearranged to solve for any of the three variables. If you need to find current, use I equals V divided by R. If you need to find resistance, use R equals V divided by I. The triangle diagram shows a helpful memory aid where you can cover the unknown variable to reveal the correct formula.
Let's work through a practical example to see how Ohm's Law is applied. We have a circuit with a 12-volt battery connected to a 4-ohm resistor. We need to find the current flowing through the circuit. Using the formula I equals V divided by R, we substitute our values: I equals 12 divided by 4, which gives us 3 amperes. This means 3 amperes of current will flow through this circuit.
Ohm's Law reveals important relationships between electrical quantities. Current is directly proportional to voltage when resistance remains constant, and inversely proportional to resistance when voltage is constant. This creates a linear relationship between voltage and current, as shown in this graph. The slope of the line equals one over resistance. In our example with 4 ohms resistance, the slope is 0.25. As we move along the line, we can see how current increases proportionally with voltage.
To summarize what we've learned about Ohm's Law: It's expressed as V equals I times R, showing the fundamental relationship between voltage, current, and resistance. Current increases with voltage and decreases with resistance. This law is essential for analyzing electrical circuits and forms the foundation of electrical engineering principles used in countless applications.