Connecting a Red LED to 230V: Power Indicator Bulb Circuit, Safety & Modification Tips

Question

Does such a scheme make sense? The red LED is to indicate power to the bulb, i.e. if the bulb is on, the diode will also. If it is bad I would ask for some modification suggestions. The entire system is connected to a 230v socket.

wniedzie · Accepted Answer

does not make sense.
I understand that you want to detect the current flowing in the main circuit. But in your schematic, both legs of the diode are connected at the same point in the main circuit, so there will be no voltage drop there. Theoretically, you could put a small 1 Ohm resistor in the main circuit, which would produce a voltage capable of lighting a diode. The problem is that depending on the power of the bulb, this resistor would have to have a lot of power, because it would heat up cruelly.
Anyway, with the right choice of this resistor, you do not need any additional elements, you just connect the LED diode parallel to the resistor.
But that's all theory. If you enter the bulb power, we can try to calculate something specifically.

wniedzie · Accepted Answer

There will always be 230V on the bulb, regardless of whether the bulb is on or not (burned out).

jdubowski · Accepted Answer

It makes no sense, and you need to connect the system in parallel to the bulb. Secondly - with such a resistance, the capacitor is not needed there. If you want to give a capacitor with the calculated Xc, reduce the resistance to 1k. Added after 1 [minutes]: And if the bulb is blown, what is going to happen?

Jarosx9 · Answer

Move this your chip above the bulb (connected to both sides), the voltage drop will be on the bulb. And choose the right resistor for the bulb power.

_jta_ · Answer

When powered through a bridge, the 0.22uF capacitor (necessarily for a voltage of at least 275V AC, it's good if it has the X2 mark) should be just right for a typical LED; with one anti-parallel diode it needs 0.47uF as you want full brightness. A resistor with not too low power (otherwise it can burn out when turned on), and add a resistor with high resistance (1M or more) parallel to the capacitor so that the capacitor discharges after disconnecting from the mains - otherwise you have a chance to discharge it through your hand and it's not pleasant.

jarek_lnx · Answer

You can make a system that will light the LED in series with the bulb, three or four rectifier diodes will give the appropriate voltage drop to power the LED

mateusz konrad · Answer

And if I connect the entire system to 12 V (12v 1-6W power supply) 3W bulb power, which scheme is better? 1 or 2 and won't the bulb shine dimmer? What resistor would be appropriate?

kortyleski · Answer

You want 230 AC or 12 DC. At 230V you need to put a small rectifying diode with the led and a 470k ohm resistor in series with the set. connect as shown in diagram 2

Freddy · Answer

System no.1 has no right to work.

_jta_ · Answer

And what is the power of this power supply? If 1W, that's not enough for a 3W bulb. And you need a bulb for these 12V (maybe from the car), not 230V.

mateusz konrad · Answer

the power of the power supply is up to 6W and the bulb is adapted to 12v

Marian B · Answer

And I will ask sillyfrant why the signaling of a glowing light bulb? After all, you can see that it shines if it is a lighting bulb, e.g. in a corridor or in a room. Sooner, the LED in the switch would be useful when the light is off. Then it is mounted on the switch contacts. Not directly, of course.

_jta_ · Answer

I once installed a LED next to the switch showing that the light is on in the next room - my grandmother sometimes forgot to turn it off, and when the door was closed, it was not visible. It is true that it was possible to drill a hole in the door and see if the bulb was lit or not ...

Connecting a Red LED to 230V: Power Indicator Bulb Circuit, Safety & Modification Tips

Post #1

Post #2

Post #3

Post #4

Post #5

Post #6

Post #7

Post #8

Post #9

Post #10

Post #11

Post #12

Post #13

Post #14

Topic summary