Ohm's Law

Definition

Ohm's law is a fundamental principle in electrical engineering that describes the relationship between the voltage, current, and resistance in an electrical circuit. It states that the current flowing through a conductor is directly proportional to the voltage applied across it, and inversely proportional to the resistance of the circuit.

5 Must Know Facts For Your Next Test

1. Ohm's law can be expressed mathematically as $I = V/R$, where $I$ is the current, $V$ is the voltage, and $R$ is the resistance.
2. Ohm's law is applicable to both series and parallel circuits, as it describes the behavior of individual components within the circuit.
3. The power dissipated in a resistor is given by $P = IV = I^2R = V^2/R$, where $P$ is the power in watts (W).
4. Ohm's law is a linear relationship, meaning that if any two of the three variables (voltage, current, or resistance) are known, the third can be calculated.
5. Ohm's law is a fundamental concept in the analysis and design of electrical circuits, as it allows for the prediction of circuit behavior and the calculation of various electrical quantities.

Review Questions

• Explain how Ohm's law relates to the behavior of series circuits.
  • In a series circuit, the same current flows through each component, and the total resistance is the sum of the individual resistances. Ohm's law can be used to determine the current, voltage, or resistance in a series circuit by applying the equation $I = V/R$ to the circuit as a whole or to individual components. For example, if the total voltage and resistance in a series circuit are known, Ohm's law can be used to calculate the current flowing through the circuit.
• Describe how Ohm's law is used to analyze parallel circuits.
  • In a parallel circuit, the voltage is the same across each branch, but the current divides among the branches inversely proportional to their resistance. Ohm's law can be used to determine the current, voltage, or resistance in a parallel circuit by applying the equation $I = V/R$ to each individual branch. This allows for the calculation of the total current, voltage, and equivalent resistance of the parallel circuit.
• Discuss the role of Ohm's law in the calculation of electric power and its applications.
  • Ohm's law is fundamental to the calculation of electric power, as the power dissipated in a resistor is given by $P = IV = I^2R = V^2/R$. This relationship allows for the determination of power consumption in electrical circuits, which is crucial for the design and operation of electronic devices, appliances, and power systems. Understanding Ohm's law and its connection to electric power is essential for analyzing the efficiency and energy requirements of various electrical applications.

Related terms

Voltage:

The potential difference between two points in an electrical circuit, measured in volts (V).

Current:

The flow of electric charge through a conductor, measured in amperes (A).

Resistance:

The opposition to the flow of electric current in a circuit, measured in ohms (Ω).