Current Limiter Resistor Calculator

Formula

The formula to calculate the value of a current limiting resistor is:

\[ R = \frac{V - V_f}{I_f} \]

Where:

\(R\) is the resistance of the current limiting resistor (Ohms)
\(V\) is the supply voltage (Volts)
\(V_f\) is the forward voltage drop across the LED (Volts)
\(I_f\) is the forward current through the LED (Amperes)

What is a Current Limiter Resistor?

A Current Limiter Resistor is a component used in electrical circuits to control or limit the amount of current flowing through the circuit. It works by providing a specific amount of resistance, which in turn reduces the current to a safe level. This is crucial in preventing damage to sensitive components within the circuit that may not be able to handle high levels of current. The value of the resistor is chosen based on the desired current limit and the voltage across it.

Example Calculation 1

Let's assume the following values:

Supply Voltage (V) = 12 V
Forward Voltage (Vf) = 2 V
Forward Current (If) = 0.02 A

Using the formula:

\[ R = \frac{12 - 2}{0.02} = 500 \text{ Ohms} \]

The current limiting resistor value is 500 Ohms.

Example Calculation 2

Let's assume the following values:

Supply Voltage (V) = 9 V
Forward Voltage (Vf) = 1.5 V
Forward Current (If) = 0.015 A

Using the formula:

\[ R = \frac{9 - 1.5}{0.015} = 500 \text{ Ohms} \]

The current limiting resistor value is 500 Ohms.