Timeline for How Zero Crossing optoisolator to work with 220VAC?
Current License: CC BY-SA 3.0
15 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jan 24, 2016 at 23:28 | comment | added | Vladimir Djukic | I research little and I found that ohm's law is diffirent for AC power... Could you do it calculation for AC? | |
| Jan 23, 2016 at 15:38 | comment | added | Vladimir Djukic | I know that but how can I know how much will voltage drop? | |
| Jan 23, 2016 at 15:35 | comment | added | Ignacio Vazquez-Abrams | @VladimirDjukic: Voltage drops when current flows. | |
| Jan 22, 2016 at 19:08 | comment | added | Vladimir Djukic | It's because I am still noob in electronics. :) I need to expreriment to understand it better, thanks for your concern but I will not apply this till I don't understand it very good. Could you answer on my previous question? | |
| Jan 22, 2016 at 16:55 | comment | added | Transistor | @VladimirDjukic: You are asking very basic electronics questions. This suggests that you are not qualified to work on mains electronics and should get some experience with low-voltage circuits where the dangers can be eliminated. | |
| Jan 22, 2016 at 14:47 | comment | added | Vladimir Djukic | Aha, ok. And is there any formule to calculate volate after current pass resistor? 220VAC when pass trought 33K resistor, does voltage drop? | |
| Jan 22, 2016 at 14:43 | comment | added | Michael Karas | You would be better advised to use two 33K ohm resistors. At 1W rating each you will have plenty of margin. If you went with a single 66K resistor it would be having ~0.8W RMS of dissipation and with a 1W component rating your margin is not nearly so good. | |
| Jan 22, 2016 at 14:29 | comment | added | Vladimir Djukic | Yes, so If I use 66K 1W resistor on 220V it will not burn LED inside opto isolator? | |
| Jan 22, 2016 at 12:51 | comment | added | Michael Karas | Are you wondering about the voltage drop across the LEDs themselves? If so that is specified as the LED Forward Voltage in the data sheet and the data sheet Figure 1. | |
| Jan 22, 2016 at 12:36 | comment | added | Vladimir Djukic | I have one more question... Is possible to calculate voltage after current go trought resistors? | |
| Jan 22, 2016 at 3:13 | comment | added | Vladimir Djukic | Thanks very much, I understand now better. I will ask u some more question if I get some more problems when I try this... | |
| Jan 22, 2016 at 3:11 | vote | accept | Vladimir Djukic | ||
| Jan 24, 2016 at 23:28 | |||||
| Jan 22, 2016 at 2:57 | comment | added | Michael Karas | Each resistor will have approximately 115 volts RMS across it. At 33K the actual RMS power in each resistor would be (115 * 115)/33K = ~ 0.4W. So it seems safe to recommend 1W resistors. If you could have good cooling air flow you may be able to get 1/2W resistors to be OK. | |
| Jan 22, 2016 at 2:49 | comment | added | Vladimir Djukic | What wattage of resistor should be? | |
| Jan 22, 2016 at 2:44 | history | answered | Michael Karas | CC BY-SA 3.0 |