LED Energie LED bulb teardown

LED Energie brand LED bulb with following data stopped to work properly:

230V 50Hz 7W E27

450lm 3000K 60mA 20D

3684 Mod.5161

So lets make a tear-down


There seems to be 20 small LEDs in series inside bulb and one of them burned black. As such this LED string is expected to need around 70V over it. LEDs were soldered to a aluminium circuit board thar was glued to aluminium tube inside plastic lamp base part.

Look at the circuit board

This looks like power supply is basically an RC current limiting (with small coil) followed by rectifier and small electrolytic filtering capacitor. In addition there are 470k bleder resistors to discharge capacitors.

The big resistor is a bit suspect here. According to color code it should be 100 ohms, but multimeter reading says 295 ohms. I suspect that either it has changed value or color code has changed colors due heating.

The RC circuit capacitor was 1.1uF 400V. The filter capacitor after rectifier was 2.2uF 400V electrolytic.

Here is the reverse-engineered circuit disgram:


  1. Tomi Engdahl says:

    IP65 LED tape coating fail

    I was using this tape above my computer for ambient illumination. Over time it imperceivably changed from warm white light to a dull orange glow.
    When it got the point that I couldn’t identify component colour bands I decided to take a closer look.

    The gel they use to make it waterproof (more like splash-proof) has degraded through exposure to the blue/violet wavelength of the light. Directly above the LED chips it had gone so brown that it was blocking and colouring the light. Initially I thought it was the phosphor that had degraded, but when the coating is cleaned off the LED it is as bright as when new.

    The LED strip was being under-run for long life, but it shows that the LEDs themselves aren’t the only factor in optical degradation. This is a good reminder that you should always treat LED tape as a consumable, and ensure it can be replaced easily in the future.

    Modifying an old light with LED tape.

    This was just a spontaneous fix of an irksome slimline fluorescent fitting that I decided to convert to a lower intensity light with some LED strip.
    My use of the current regulated supply isn’t ideal since it means that if sections of LEDs fail the current through the remaining ones will increase. It was just hard finding a tiny 12V supply that would fit inside the slim casing.
    If I’d had thicker wire to hand I’d have used it. But the stuff I used is more than capable of surviving a fault current that will take out the 3A fuse in the plug. (Continuous rating 2A.)

  2. Tomi Engdahl says:

    A troubling trend in lighting?

    Is this a bright idea? Or will it eventually leave you in the dark?

    00:00 Intro
    01:56 A brief (hah!) history of electric lighting
    04:28 Ballasted light sources
    07:59 The freedom of LEDs
    08:49 The thing the video is about
    09:26 Electrical boxes and wiring
    11:10 Why the idea is so appealing
    12:02 All the advantages
    17:17 And now for the problems
    21:22 The idea is spreading – should it?
    23:08 Some light bulb longevity advice
    25:25 Thermal cam footage of filament-style LED bulb
    27:19 I hope you will consider PAR-style lamps if you can
    28:36 Smooth jazz and bloopers

  3. Tomi Engdahl says:

    Inside a high voltage LED

    A look through a microscope at a high voltage 24-LED array in a tiny 2835 style package.

    Quick correction, I worked out that roughly 18V is being dropped across the linear regulator. Not 18mA like I said. The combined voltage of the LEDs is so high that very little more has to be dropped across the regulator. That keeps its temperature down. If it did get too hot it would probably self regulate the current down further.

  4. Tomi Engdahl says:

    page about batteries, chargers and flashlights


  5. Tomi Engdahl says:

    Bare 230V LED tape

    I’m not sure what application this bare mains voltage LED tape is intended for, but the implication in the listing that it can be used under kitchen cabinets, in bathrooms and children’s play rooms may not be appropriate.

    Despite operating at full mains voltage, this tape can still be cut every 100mm (4″) and does not need an external rectifier. It achieves this with built in rectifiers, multi-chip LEDs and current limiting resistors. Rather pleasingly it doesn’t grill them for a change – even on a 245 volt supply.

    The listing actually showed a linear current regulator on each section, but the tape that arrived has resistors. That’s fine. It means there may be a slight intensity change with voltage fluctuations, but the resistors are going to be much more reliable than an active component.

    The track spacing is squirmy for the voltages involved. This tape is not suitable for use anywhere with even the slightest risk of condensation forming, and if mounted onto a metal backing there is very little between mains voltage and the surface it’s mounted on. Even hygroscopic adhesive could pose an issue.

    The only places this tape could be used are in well insulated or grounded enclosures to avoid the risk of it being touched. The possibility of the tape parting from its adhesive would have to be considered, and it definitely needs a low value fuse.

  6. Tomi Engdahl says:

    Building my own “Dubai Lamps”

    How to build your own “Dubai Lamp” – an LED lamp that runs LEDs at a reduced current (lower power) to improve the efficiency and prolong its life. This was my first attempt to make LED lamps more efficient.

  7. Tomi Engdahl says:

    Inside a new Philips ultra-efficient LED lamp (with schematic)

    I was hoping this lamp was going to have similar circuitry to the Dubai lamp, which is not sold in other countries, and while it does have the same concept of under-run LED filaments for long life and higher efficiency, it uses fairly standard circuitry inside.

    The one interesting feature of the circuitry, and also the bit that took me longest to reverse engineer because it caught me off-guard, is a novel design twist that reduces the voltage across the chip. The inclusion of transient clipping resistors and filtering should also add to the reliability.
    It’s been pointed out that the circuit configuration will also increase the efficiency slightly, as the chip current will contribute to the LED current.

    I’m surprised that a linear regulator wasn’t used as in many other lamps due to the simplicity. It’s possible that this lamp has been in the design stages for a while and used buck regulator circuitry as a result of that. The choice of 100V filaments is possibly to cater for 120V and 230V options. Tuning filaments for linear regulators is a bit more complex than the multi LED arrays.

    I’m surprised that a linear regulator wasn’t used as in many other lamps due to the simplicity. It’s possible that this lamp has been in the design stages for a while and used buck regulator circuitry as a result of that. The choice of 100V filaments is possibly to cater for 120V and 230V options. Tuning filaments for linear regulators is a bit more complex than the multi LED arrays.

    The high cost of this lamp (I paid £12 at John Lewis in the UK) is purely for the life/efficiency features. In the right location it will pay its way by reducing power and maintenance costs. Especially where architects/designers have put light fittings in locations that make servicing them difficult or hazardous.
    In the home it could be useful in areas like halls and stairways where the lights are used a lot during the day.

  8. Tomi Engdahl says:

    Pound shop USB disco light teardown (with schematic)

    I think the best lesson that can be learned from this cheap USB disco light is the importance of supply rail decoupling in the vicinity of audio circuitry.
    There’s an audio amplitude detector circuit that triggers continually when used on anything other than a perfectly noise free USB power supply.

    That said, it’s a good demonstration of a simple electret microphone based audio detector with a minimalist single transistor amplifier.
    The lens projects fairly good beams of light from the hard-driven (50mA) LEDs, so it might find use in other projects.

  9. Tomi Engdahl says:

    New LED lamp twist reverse engineered from a picture

    Just when you thought they couldn’t make an LED lamp simpler than the common linear regulator type, they come out with this.

    It’s basically a single package combining the rectifier and current regulator into a single package.

  10. Tomi Engdahl says:

    Make custom LED neon shapes

    LED neon or LED flex is a very handy material for creating neon-like signage and effects.
    As time goes on it’s harder to find places that still make traditional glass neon. This is largely due to the advances made with LED technology providing a safe low voltage alternative for illumination of channel letters signs, and novel materials like this that emulate the traditional linear lines of neon.
    Cost is a major factor too. While the LED neon flex won’t last as long as a properly processed neon tube, it is easier to drive and much more tolerant of rough handling.

    This project uses short pieces of LED neon flex to create very punchy looking geometric shapes. It’s perfect for using up residual scraps from other projects.

  11. Tomi Engdahl says:

    Prototype mains LED lights

    Exploring some very early prototype LED panels from when gallium nitride LEDs first appeared on eBay (the dumpster ones!) and made projects like this viable.
    I also appear to have inadvertently predicted the use of large arrays of LEDs with simple current limiting as used in modern lamps, albeit with each LED containing large numbers of separate LED dice.
    Perhaps I should revisit this project and add a two transistor regulator for stable current regulation on bumpy supply voltage.

    I like the idea of 3D printing a custom housing too.


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