3.2-3.4v @ 25ma is the rating for the LED's, if I were to string 36 of them in series, that makes 118v give or take. Unless I misunderstand, all I would need then is a current limiting resistor (56 ohms by my calculator) per string of 36 LED's. This also works out conveniently to just about three watts exactly per string, including the dissipation from the resistor.

**I'd go with Jack's calculations...** With 56 Ohms, you'll get about 1Amp peak through the LEDs and probably fry 'em all! (I assume your mains voltage is 120V (not 220V)?

**One more consideration -** The voltage across the LED's is approximately constant. That means the less voltage you drop across the resistor, the worse your "brightness regulation". With 50V across the resistor, a 10% change in the 170V peak voltage is 17V. That entire

*change* appears across the resistor, which means a 34% change in current (and brightness). So with an unregulated power supply,

**don't try** to stack-up as many LEDs as possible in order to minimize the voltage across (and power wasted in) the resistor.