carbonblack
- Jul 16, 2022
- 3
- Joined
- Jul 16, 2022
- Messages
- 3
Won't the LED act as a half wave rectifier in this case and the average voltage will be less than 228V.In an ideal world, 230V - 2V = 228V across the resistor. But we don’t live in an ideal world and 230V will certainly vary (quite a bit).
In your schematic the current through the LED is 20mA so an absolute minimum of 5W resistor but larger is highly recommended as suggested above. Lowering the LED current allows for smaller wattage resistors. 1mA you might get away with 1/4W but 1/2W would be recommended.
What is it for? A power indicator?.
It will probably be flashing visually to AC frequency which isn’t nice and is very crude. You could add an inverse parallel diode or a series diode. But I don’t see the point.
Martin
Yes of course. Why not?And is it gonna be still AC voltage across the LED?
I'm not going to practically do this. I just needed a theoretical explanation. That's all. Thank you for replying.Yes of course. Why not?
This setup will not work at all. On the negative part of the sine wave (negative with respect to the forward direction of the LED) the LED will be reverse biased by 325 V (230 V × sqrt(2)). The LED will break down much earlier and will be destroyed.
I'm not going to practically do this. I just needed a theoretical explanation.