Dr Ronald Stiffler SEC technology

[itsu]

Hi Itsu,
Many thanks.  This may mean the series capacitance of the back plate of your LED board towards the conducting LEDs and the two diodes common point is small enough so that the variable capacitor can still be tuned for max brightness, I suppose?
Okay that a smaller current yields less brightness, I thought to reduce it so that such changes should not damage anything.
Gyula

Yes,  the 6-60pF variable cap is still somewhere in its middle range.

Itsu

[gyulasun]

Okay, that is good news, especially if the waveform across the tank remains relatively nice sine wave.


Thanks for the LED specs.  Is there any internal circuit you gutted from the board you use?  Because the original is specified as usable from 90V to 260V AC, this means a DC-DC converter embedded and fed from a full wave bridge rectifier to take care of the AC input.

The 5050 SMD LED chip generally runs at 60mA and forward voltage ranges between 3.1 and 3.4V, this is roughly 0.2 W. Your board has 14 chips, this would give 14 x 0.2 = 2.8W for that board. I do think that it is a marketing policy to advertize the original LED lamp as a 11W device, the brightness is enhanced by the mirror surfaces but the input power must be around 9 W or so and not 11 W as specified.

Here we can find the 5050 LED chip specifications
https://www.superbrightleds.com/moreinfo/surface-mount-smd/warm-white-5050-smd-led-120-degree-viewing-angle-6000-mcd/317/1249/ 

I think the 14 LEDs on your board are in series connection, if this is so than this means the forward voltages add up to say 3.3V x 14 = 46.2 VDC and considering 60 mA as specified, input power would be 2.77 W. 
This mean that such gutted LED board does not need 230V input, right?  I think the DC-DC converter steps down the 90 to230 V input AC to to this 46V DC and the 3 LED boards in the original lamp is connected in parallel. 

The DC input now is 12.5 x 62 mA= 0.775 W  and if the brightness would be comparable to the 2.7W DC input fed directly to such gutted board, then you have something good      It would be too good to be true...
Gyula

[itsu]

Yes, i removed the internal circuit (packed in yellow tape) but cannot find it now.

I tested another of the 3 led strips and with 16V i see some glow in the 14 leds appear
Crancking up the voltage untill 60mA current is drawn shows 20V, but this is not near the brightness it should be.

At 24V (200mA) the leds are very bright and the backplate start to get hot (40°C and rising).
The 3 led strips are mounted normally on a bigger alu heatsink, so i guess the 24V could be about its operating voltage.

I dont think the separate led strip will survive 46V, so probably the 14 leds are not in series.

Itsu

[gyulasun]

Hi Itsu,
Thanks for checking this.  If I recall correctly the LEDs should be connected in series on the board, when driving it capacitively through the Alu plate,  the Doc mentioned this in one of his videos and earlier for the SEC circuits he wrote a doc on the different connections "An efficient method for driving LED arrays", see attached. 

I agree the 14 LED chips on your board should be in a combination :  like 7 in series and the other 7 are also in series and these two series strings then connected in parallel.  This would be in the ballpark electrically I think.  That would mean 2 x 60 mA = 120 mA  and 7 x 3.3V = 23.1 V giving 2.7 W input,  with a brightness that is specified for this 5050 LED chip.

Gyula

[iQuest]

NickZ and others:  If I may be of help, you can get the genuine SEC 18 L3 coil information you're looking for 'straight from the horse's mouth'.  On the first page of this thread, ramset attached a document
by Dr. Stiffler which provides a very detailed description of the L3 coil construction which starts on page 30.  See Reply #10 on October 17, 2017, attachment file name DocumentSEC18_Rel_2_8-1.pdf 
https://overunity.com/17249/dr-ronald-stiffler-sec-technology/10/