Hi, my first post on the forum will be to ask about LEDs. I thought I knew all there was to know about LEDs until today I was fooling around in after hours with a LED circuit fed directly from my 220 VAC mains line and observed a few things I'd never known.
1) I fed a LED from the 223 VAC RMS mains line in series with 2 10k resistors. I plugged it in and checked the voltage across the LED terminals and it was 76 VAC, the LED was cool, light was moderate, resistors were warm. Left on for over a minute. How can this voltage be possible and not blow the LED?
2) I fed the same circuit on 122 VAC RMS and voltage drop across the LED was now 60V. If the proportion 122/223 was maintained, the voltage should be 41.5 V across the LED. How is a nonlinear circuit possible with a LED? Again, 60V and the LED was cool, resistor warm to the touch.
3) So I exaggerated he resistor adding a 2M2 resistor, connected to a 223 VAC line. The LED didn't light up, but surprisingly the voltage drop across the LED was still 60VAC
Other resistor values tested:
110K VLED 66V
10K VLED 84V
Any ideas why the LED stays intact? Why is the LED voltage drop nonlinear?
Thanks in advance for any pointers.
1) I fed a LED from the 223 VAC RMS mains line in series with 2 10k resistors. I plugged it in and checked the voltage across the LED terminals and it was 76 VAC, the LED was cool, light was moderate, resistors were warm. Left on for over a minute. How can this voltage be possible and not blow the LED?
2) I fed the same circuit on 122 VAC RMS and voltage drop across the LED was now 60V. If the proportion 122/223 was maintained, the voltage should be 41.5 V across the LED. How is a nonlinear circuit possible with a LED? Again, 60V and the LED was cool, resistor warm to the touch.
3) So I exaggerated he resistor adding a 2M2 resistor, connected to a 223 VAC line. The LED didn't light up, but surprisingly the voltage drop across the LED was still 60VAC
Other resistor values tested:
110K VLED 66V
10K VLED 84V
Any ideas why the LED stays intact? Why is the LED voltage drop nonlinear?
Thanks in advance for any pointers.