Although supplied in an identical box to the ES version of these festoon-style LED lamps, this one has slightly different circuitry.
The ES version of the lamp had a ring of diffused LEDs wired as two inverse parallel strings with a capacitor and resistor in series, but this one has a cap, rectifier and some smoothing. There's also a series resistor in line with the LEDs, and to accommodate the small amount of space on the PCB it is mounted mid-way through the circle of LEDs. This means it can go in any available space on the PCB.
The white LEDs themselves are an unusual size that looks like 4mm diameter, and are clear lensed LEDs. Unfortunately this means they project quite a hotspot of light onto the front of the lamp globe.

One thought on “Sudden schematic of a slightly different led festoon lamp.”
  1. Avataaar/Circle Created with python_avatars The Philpott says:

    Mr Clive, just bought some interesting Crompton LED (GLS shape/size) ES garden bulbs to save power in a string of what was Twenty filament bulbs of 25w each. The replacements i got have a conventional glass envelope with pigment applied to the inside of the glass. (quite well, as it happens.) They are advertised as 2w each however the box gives away that they are 1.5w each.

    A couple of them failed straight away but the supplier replaced them and i got to keep the 2 duds since the postage wasn't worth it. I busted one of them open. Up the middle of the bulb is an aluminium pylon with 19 leds attached, 16 around it and another 3 on the end. A resistor and (ceramic capacitor??) were included. The LEDS appear to be based on a conventional tape which has been adapted/bastardised to suit the shape of the pylon.

    They quote the Lumens for the red and green ones at 25, amber at 50, yellow at 95 and the blue at 7. The visual impact of them all is quite impressively linear though, and the light distribution is very even across the glass envelopes. The colour rendering of the blue ones is, as you would expect, spectrally way superior to the filament bulbs they have replaced.

    I am not sure whether all the LED's are 'white' or whether they are tailored ones which are then 'smoothed' by the coloured bulb. I suspect the former. Let's not mess about, at £5 each the only savings are in respect of future bills, but blimey they really do run cool, which should extend the life of the waterproof shrouds round the neck.

    I still have the other faulty one if you want to reverse engineer it. Not VERY interesting inside though.

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