For those who want to try it out without building your own circuit boards, ... 10 thoughts on “ LED Ring Around The ESP8266 ” Cknopp says: September 12, 2015 at 1:10 pm ...

LED has become more and more popular for use as light indicator because of its low cost and long life. Unfortunately the LED works only at low voltages and even then you need to use a resistor in ...

I needed a simple LED indicator showing that a particular voltage level had been reached—specifically, ... With the circuit values shown, R2 will drop a bit less than 5 V before D3 turns on.