History
Ohm’s Law was formulated by German physicist Georg Ohm in 1827. He conducted experiments on electrical circuits and discovered a relationship between the voltage, current, and resistance. Ohm published his findings in his book “Die galvanische Kette, mathematisch bearbeitet” (The Galvanic Circuit, Mathematically Treated) in 1827.
Ohm’s Law
Ohm’s Law is a foundational principle in electrical engineering that describes the relationship between voltage, current, and resistance in an electrical circuit. It states that the voltage (V) across a conductor is directly proportional to the current (I) flowing through it, provided the temperature and other physical conditions remain constant.
The Formula:
Mathematically, Ohm’s Law is expressed as:
V = IR where:
V is the voltage (potential difference) across the conductor, measured in volts (V) I is the current flowing through the conductor, measured in amperes (A) R is the resistance of the conductor, measured in ohms (Ω)
Understanding the Components:
Voltage (V): Voltage is the electrical potential difference between two points in a circuit. It is essentially the “push” that drives the current through the conductor. Current (I): Current is the rate of flow of electric charge through a conductor. It is measured in amperes (A). Resistance (R): Resistance is the opposition to the flow of current in a conductor. It is measured in ohms (Ω). A higher resistance means that a conductor offers more opposition to the flow of current.
Applications of Ohm’s Law
The formula for Ohm’s Law can be rearranged to solve for any of the three variables:
To find current (I): I = V/R To find voltage (V): V = IR To find resistance (R): R = V/I
Limitations and Considerations
While Ohm’s Law is a powerful tool, it has certain limitations:
Temperature Dependence: Ohm’s Law assumes that the resistance of a conductor remains constant. However, in reality, the resistance of most materials changes with temperature.
Nonlinear Components: Ohm’s Law is not directly applicable to nonlinear components such as diodes and transistors, whose resistance varies with the applied voltage or current.