3. R1 don´t warm soo much, not need big dissipation
Quote3. R1 don´t warm soo much, not need big dissipationYes but I think you need a bigger resistor than that, that is more power than just 0.125W.Also note the voltage rating on C1.I used a similar circuit on a set top box and the 0.25W resistor caught on fire when C1 failed.
In the schematic with the capacitor in series with the optocoupler's LED, what is the function of the capacitor? I know you can limit AC current with a series capacitor, but why is the resistor alone not enough?
I used a similar circuit on a set top box and the 0.25W resistor caught on fire when C1 failed.This was tested in the safety lab where I worked
Isn't a current sensor, like this onehttp://www.seeedstudio.com/depot/noninvasive-ac-current-sensor-100a-max-p-547.html?cPath=144_154a much safer and reliable option for this purpose?