For ........... the graph of current and voltage is not a straight line and value of resistance is not constant.
For Tungsten.
For non-linear elements, such as diodes and transistors, the graph of current and voltage does not follow a straight line. Instead, it exhibits a non-linear relationship where the value of resistance is not constant.
To understand why the graph of current and voltage is non-linear, we need to consider the behavior of these elements. Unlike linear elements, non-linear elements do not obey Ohm's Law, which states that the current flowing through a component is directly proportional to the voltage across it, given a constant resistance.
For example, in the case of a diode, when the voltage across it is below a certain threshold (often referred to as the forward voltage), the diode acts like an open circuit, allowing very little current to flow. However, once the voltage exceeds this threshold, the diode becomes conductive, allowing a significantly larger current to flow through it.
This non-linear behavior is due to the specific characteristics of the diode, such as its junction behavior and semiconductor properties. Similarly, other non-linear elements like transistors or light-dependent resistors (LDRs) also exhibit varying resistance based on the voltage or current applied.
To determine the current and voltage relationship for such non-linear elements, manufacturers provide specifications like voltage-current curves, transfer curves, or characteristic curves. These graphs represent the behavior of the element and provide a visual representation of how the current and voltage are related.
Therefore, when dealing with non-linear elements, it is important to consider the specific characteristics and use the provided specifications or models to understand their behavior accurately.