Hi ToddB74,
You seem to want to make this indicator light as complicated as possible. If you look at the absolute maximum rating for the LM317T you will see that the maximum input/output differential is 40 volts. So to use this you first need to drop the voltage down to less than 41.8 volts DC (assuming a 1.8 volts LED) To do this you would need the capacitor (Slightly different value.) and resistor of Tony's second circuit followed by a bridge rectifier and smoothing capacitor to provide the DC input to the LM317T This would be a very bad design as using the reactance of the capacitor to drop the voltage provides more of a constant current source than a constant voltage source. The input voltage to the LM317T would be defined mostly by the current output of the LM317T (This would apply weather you configured LM317T either as a constant current regulator or as a constant voltage regulator with a resistor on the output to set the LED current.) You could get round this problem by adding a 40 volt zener diode in parallel with the smoothing capacitor. A further reason that using the LM317T to drop the voltage by 40 volts is it would generate extra heat (40V x 20 mA = 800 mW)
Les.[/QUOTE
Les.......Thanks for straightening me out on that !
I got the idea from reading a document on LEDs, titled
Problems Using Resistors to Regulate Current at the following website >
http://www.reuk.co.uk ( Click-on this article >
Using The LM317T With LED Lighting - Lighting )
So
I'll forget about using the LM317T voltage regulator on my current application.
I appreciate you're taking the time to explain.
ToddB74