Calendar

November 2017
M T W T F S S
« Jun    
 12345
6789101112
13141516171819
20212223242526
27282930  

Categories

Active supporter of WikiPedia
Support Wikipedia

Geocaching

Profile for uwezi

Top deal of the week?

Unschlagbares Angebot der Firma Elektor.

Today I received a newsletter from the publisher Elektor. I am offered a special deal on a Peltier power generator which can power an LED light from a small candle. And this for an astonishing price of €99.95 instead of the normal price of €119.95.

Great offer from Elektor.

I’ll have to buy […]

Continue reading Top deal of the week?

Fakes from China

s-l500

Inspired by a Youtube video from Bigclive I ordered some Solar Power Rechargeable Flash lights. I knew the risk but I thought it would be a possible way to get hold of some small amorphous silicon solar cell modules for some own projects.

yeah – a bang good solar flash light

Today I […]

Continue reading Fakes from China

That’s bright!

IKEA LEDARE lamp with 16.5 W and 1000 lm.

Transatlantic recently asked about a new IKEA LED lamp, the LEDARE with 1000 lm.

It comes as a quite big globe (diameter 95 mm) with an E27 socket, an electrical power rating of 16.5 W and is supposed to be dimable!

Transatlantic commented on the high quality of the warm-white light output and wondered […]

Continue reading That’s bright!

LED lamps are (not) forever

_IGP9525a_600

Two weeks ago I wrote about my experience with special price offers for LED bulbs at Bauhaus. What I didn’t write was that I then just went to the other side of the street – well almost – and bought a 2.2 W E14 LED bulb at Jula.

2.2 W E14 LED light […]

Continue reading LED lamps are (not) forever

special offer at Bauhaus

Special offer on LEDs at Bauhaus: new price twice as high as before!

Today I was at Bauhaus in Uppsala, just browsing, not looking for anything special. Close to the exit there was a table with LED light bulbs which were obviously taken out of the regular assortment and re-labelled with new prices.

Usually you would expect a bargain – and since I am somewhat sold to […]

Continue reading special offer at Bauhaus

Merry Christmas!

14seg_xmas

[jwplayer mediaid=”1242″]

[jwplayer mediaid=”1241″]

[jwplayer mediaid=”1225″]

[jwplayer mediaid=”1238″]

Magic lights in Uppsala

23rd UNT fireworks

Today the art festival “all lights on Uppsala” ended and Christmas season officially started with the 23rd annual fireworks by the local newspaper UNT.

23rd UNT fireworks in Uppsala

All lights on Uppsala – Gillbergska genomfarten

During the festival, the artists and the city officials wanted to emphasize why LEDs will be […]

Continue reading Magic lights in Uppsala

The best LED bulb? – part 2

Top-side view of the power supply.

Ok, let us continue the reverse engineering of the E27 LED bulb LEDARE from IKEA. After describing the actual light emitting diode assembly in the previous post, I will today look deeper under the hood into the power supply.

Disassembling the socket of the clear E27 LED bulb LEDARE from IKEA to reveal […]

Continue reading The best LED bulb? – part 2

The best LED bulb?

The LED chips in the LEDARE light bulb from IKEA, photographed in their own light at a forward current of about 1 mA per string - under normal operation the current per string is about 240 mA).

At least the best one I have seen so far. After giving a lecture on LEDs yesterday I finally unpacked and tested my latest buy – the clear E27 LED bulb LEDARE from IKEA.

The clear E27 LED bulb LEDARE from IKEA. (Image linked from IKEA’s homepage.)

The specs of this LED bulb […]

Continue reading The best LED bulb?

…another watt saved…

The LED driver and the 20W LED.

A few days ago I posted my driver prototype for a 20 W, 700 mA, 32 V white LED. Under best conditions I reached 85% of power conversion efficiency between the 12 V input and the electrical power delivered to the LED. I was not satisfied and one of my suspicions were substantial losses in the power MOSFET.

[…]

Continue reading …another watt saved…