The cheap Chinese bulb that won't turn off
Why Electrical Engineering Stack Exchange recommends it
Electronics Stack Exchange users link it when someone asks why an LED lamp still glows dimly after the switch is off, since it explains the capacitive coupling behind the effect.
Recommended by 0 people across 0 different months, 2022 to 2023.
What it is
Steve Mould investigates why some cheap LED bulbs keep glowing faintly or drawing mains power after being switched off. He walks through the circuit inside the bulb and explains the effect, building on Mehdi Sadaghdar's ElectroBOOM video on the same oddity.
What people said
Cites mo FEAR · 2022-01 · Electrical Engineering Stack Exchange · on “Why does a mains LED lamp attached to an inverter glow dimly despite being switched off?”
I have 220V AC LED lamps (bought from eBay) connected to a 1000W pure sine wave inverter, which itself is connected to a car battery. There is a ususal on/off switch between the lamp and inverter on the "hot" wire (called L or phase). Strangely and unexpectedly, the lamp glows dimly (at about 10%) even when off. The LED lamp has a ceramic capacitor in it, along with another unidentified component (that looks like an IC or transistor.) I assume the capacitor (and other component) is to smoothen "flutter" due to mains frequency, but my assumption is that no non-negligible current can flow through it as long as one of the wires (be it phase or neutral,) is disconnected. I know parasitic capacit
Cites DrakeJest · 2022-02 · Electrical Engineering Stack Exchange · on “How to fix LED fixture not turning off completely when the switch is off”
I have LED ceiling lights that are not completely turning off even when the switch is off. [LINK] Sometimes the brightness of the glow is just to much for me and finally decided to do something about it. This video by steeve mould [this video] tried to explain what is going on but did not offer a solution on how to fix the issue. The PCB on 8:11 [this video] looked really similar to what mine uses. The solution to the problem though is on another video by Electroboom [LINK] saying to place a 470 kohm resistor on the output of the rectifier. [LINK] The circuit that electroboom is using is not the exact same circuit as I have. So will it still work? And how do I calculate the value of the resistor for m
Cites 15 Volts · 2023-07 · Electrical Engineering Stack Exchange · on “LED lights don't turn off completely”
The problem you're encountering is typically caused by capacitive coupling in elongated cable runs (for a detailed explanation, refer to this video: [this video] ). I believe using a Zener diode might not prove successful in an AC context. This is because even with Zener diodes rated for higher voltages, a short circuit could potentially occur during half of the AC cycle. An alternative approach could be linking two similar-rated high-voltage Zener diodes in an inverse-parallel arrangement, or perhaps using a Transient Voltage Suppression (TVS) diode. However, these options may not rectify your issue. These methods are more suited for creating a surge protectors or spike guard, rather than reduci