Timeline for Can I connect 500K resistor directly to the mains?
Current License: CC BY-SA 3.0
8 events
| when toggle format | what | by | license | comment | |
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| Jan 21, 2019 at 14:17 | comment | added | EmbeddedGuy | I do not recommend using one resistor. In life it happens that the purchasing department will get cheaper resistor, incorrectly missing its inappropriate lower voltage rating, especially with SMD resistors. the solution is be safe and always put 2 resistors in series (of course with half of the desired resistance each). This is what I use in my designs for 240Vrms AC. Or go crazy, for industrial high reliability devices I have seen 4 resistors in series in 240Vrms AC. | |
| Oct 24, 2015 at 4:20 | comment | added | RJR | Thanks all, I've added a correction for AC to be on the safe side. | |
| Oct 24, 2015 at 4:19 | history | edited | RJR | CC BY-SA 3.0 |
Correct AC voltage peak
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| Oct 22, 2015 at 15:39 | comment | added | KyranF | so yes, I agree the full voltage rating should deal with the max possible instantaneous voltage including the fact that AC voltage goes ~1.4x higher than what is written, and then from that, do the x1.5/x2 safety factor. Unless of course you like living on the edge and enjoy a flash-over/spark across the resistor at 50/60Hz | |
| Oct 22, 2015 at 15:37 | comment | added | KyranF | @OlinLathrop the important part is the datasheet actually says that too, "Operating voltage, Umax. AC/DC" | |
| Oct 22, 2015 at 11:32 | comment | added | Olin Lathrop | 250 V is not a sufficient rating for 220 VAC. The peaks will be over 310 V. You need a resistor rated for at least 350 V, preferably 400 V. | |
| Oct 22, 2015 at 10:18 | vote | accept | Michael George | ||
| Oct 22, 2015 at 7:35 | history | answered | RJR | CC BY-SA 3.0 |