Ohm’s Law is a fundamental principle in electrical engineering and electronics that describes the relationship between voltage (V), current (I), and resistance (R). It states that the current through a conductor between two points is directly proportional to the voltage across those points, as long as the resistance remains constant. This law applies to circuits with purely resistive elements, whether the voltage or current is direct current (DC) or alternating current (AC).

Ohm’s Law Formula

Ohm’s Law can be expressed in three forms:

1. V = I × R
   • V: Voltage (Volts)
   • I: Current (Amperes)
   • R: Resistance (Ohms)
2. R = V / I
   (Resistance is the ratio of voltage to current.)
3. I = V / R
   (Current is the ratio of voltage to resistance.)

These equations allow for easy calculation of one variable when the other two are known, making Ohm’s Law an essential tool for designing and analyzing electrical circuits.

Electrical Power and Ohm’s Law

In addition to current and voltage, Ohm’s Law also helps in calculating electrical power (P), which represents the rate at which electrical energy is transferred or consumed. Electrical power is typically measured in Watts (W).

The relationship between power, voltage, current, and resistance is derived using Joule’s Law combined with Ohm’s Law:

1. P = V × I
   (Power is the product of voltage and current.)
2. P = V² / R
   (Power can also be calculated using voltage and resistance.)
3. P = I² × R
   (Power can be calculated using current and resistance.)

Ohm’s Law Formula Wheel

The Ohm’s Law formula wheel visually represents the relationships between voltage, current, resistance, and power. To use it, simply select the variable you want to solve for in the center of the wheel, then apply the appropriate formula based on the known variables. The formula wheel is a handy reference for quickly solving electrical circuit problems.

Key Applications of Ohm’s Law:

• Circuit Analysis: Ohm’s Law helps in understanding how voltage, current, and resistance interact in an electrical circuit.
• Component Design: It is crucial when designing electronic components like resistors, to ensure they handle specific currents and voltages.
• Power Management: Calculating power usage for electrical devices, ensuring safe and efficient operation in homes and industries.