What can I do to drive the LED? The small details to note are

What can I do to drive the LED? The small details to note are

LED (light emitting diodes) light emitting diodes. The light emitting diodes can only conduct (power on) in one direction, which is called forward bias voltage or forward voltage (VF), and its current is called forward current (if: forward current). LED is a constant current element, current and voltage will affect the color and brightness of LED. When the voltage reaches the minimum demand of the forward voltage of the LED, the LED can be driven. There is voltage and current. The LED is a constant current element, so the current limiting resistance (R) needs to be connected in series. The limiting current cannot exceed the forward current of the LED. The forward current of the general LED is 20mA (refers to the LED used for general indication, which is not a high-power LED). The current limiting resistance can be obtained by Ohm's law r = (VCC VF) / if. In addition, it should be noted that the reverse voltage will breakdown the LED and cause damage.