Can Ohm's Law be used to calculate the voltage across a diode or an LED?
1 Answer
Ohm's Law can only be directly applied to calculate the voltage across diodes or LEDs when they are operating in their "on" state or conducting state. Diodes and LEDs are semiconductor devices that have a non-linear relationship between voltage and current, unlike resistors, which have a linear relationship.
Ohm's Law states that the voltage (V) across a resistor is equal to the current (I) passing through it multiplied by its resistance (R), expressed as V = I * R. This relationship holds true for resistors because their resistance remains constant regardless of the applied voltage or current.
However, diodes and LEDs have a specific voltage drop across them when they are conducting. For a standard silicon diode, this voltage drop is typically around 0.6 to 0.7 volts, while for an LED, it can vary depending on the color and material but is usually within a similar range. The voltage drop across these devices is not directly proportional to the current flowing through them, making Ohm's Law insufficient for accurately predicting their behavior.
To analyze the voltage across a diode or an LED in more detail, you need to consider their specific voltage-current characteristic curves, which show how the voltage drop varies with current. The simplest way to determine the voltage across these devices is to use datasheets or characteristic curves provided by manufacturers.
In summary, Ohm's Law cannot be used directly to calculate the voltage across a diode or an LED. Understanding the device's voltage-current characteristics and using appropriate models are essential for accurate analysis.
Ohm's Law states that the voltage (V) across a resistor is equal to the current (I) passing through it multiplied by its resistance (R), expressed as V = I * R. This relationship holds true for resistors because their resistance remains constant regardless of the applied voltage or current.
However, diodes and LEDs have a specific voltage drop across them when they are conducting. For a standard silicon diode, this voltage drop is typically around 0.6 to 0.7 volts, while for an LED, it can vary depending on the color and material but is usually within a similar range. The voltage drop across these devices is not directly proportional to the current flowing through them, making Ohm's Law insufficient for accurately predicting their behavior.
To analyze the voltage across a diode or an LED in more detail, you need to consider their specific voltage-current characteristic curves, which show how the voltage drop varies with current. The simplest way to determine the voltage across these devices is to use datasheets or characteristic curves provided by manufacturers.
In summary, Ohm's Law cannot be used directly to calculate the voltage across a diode or an LED. Understanding the device's voltage-current characteristics and using appropriate models are essential for accurate analysis.