Use APKPure App
Get LED (Light Emitting Diode) old version APK for Android
Practical design guide using LED.
An app to calculate the value of the voltage drop resistor and power rating in a series connected LED. It also has the option to calculate the value of a branch resistor in the case of a circuit board that requires large sink currents. You can use this calculator to get the value of the branch resistor. Why would you need an LED in that case. You want a visual indication ON/OFF or HI/LO.