Current Limiting Resistors (One use of resistors)
A current limiting resistor is a resistor that is used to reduce the current in a circuit. A simple example is a resistor in series with an LED.
You would usually want to have a current limiting resistor in series with your LED so that you can control the amount of current through the LED. If too much current is going through your LED, it will burn out too fast. If too little current is going through it, it might not be enough to light the LED. Check the datasheet of your component to find forward voltage drop (Vf) and the appropriate forward current (If) for your LED. You will also need the input voltage (Vinput or Vs), which from an Arduino pin is 5V. You can then use the equation on the right to calculate the required resistance of your fixed resistor. Check out this site for more information. |