What is Ohm's Law?
**Ohm's Law** states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points, provided the temperature and other physical conditions remain constant.
Formula:
- **V = I × R**, where:
- V = Voltage (in Volts)
- I = Current (in Amperes)
- R = Resistance (in Ohms, Ω)
Graphical Representation
In an ideal conductor, the graph between Voltage (V) and Current (I) is a straight line passing through the origin. The slope of the line represents the resistance (R).
**Explanation**: The linear graph shows that as voltage increases, current also increases proportionally for a constant resistance.
Limitations of Ohm's Law
While Ohm’s Law is widely applicable, it has certain limitations:
- Ohm's Law is not valid for **non-linear devices** such as diodes and transistors, where the relationship between voltage and current is not linear.
- It does not apply to **vacuum tubes** or **semiconductor devices**.
- The law is invalid for materials that change resistance with **temperature**, such as thermistors or superconductors.
- Ohm's Law does not consider the **frequency** of the applied voltage in AC circuits.
- It assumes the conductor is **homogeneous** and isotropic, which may not always be the case.