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 specs of this LED bulb are not overly impressive, with an efficacy of a mere 50 lm/W it is about… Continue reading The best LED bulb?

DIY STK505 replacement

The adapter board attached to the STK500's ISP10PIN header.

The Atmel STK500 development board does support many but not all of Atmels AVR controllers. As an enhancement a STK505 unit was constructed by Atmel to support the ATtiny24/44/84 series of microcontrollers, which come in a 14-pin DIP package. Other plugin-boards for other pinouts have also been made, but since the STK500 itself is considered… Continue reading DIY STK505 replacement

Counterfeit electronics?!

Genuine part or counterfeit? Two supposedly identical chips, one a sample from the manufacturer, the other one bought online from Chinese sellers on eBay. One is working, the other one is crap...

My latest post was about differences within legitimate versions of the same integrated circuit from different manufacturers, today I’d like to write about experiences with supposedly counterfeit components. It has been in the media that the electronic component market is fighting with counterfeit products from the far east. I myself encountered possible indications of such… Continue reading Counterfeit electronics?!

Winter orchids

Three of my orchids are currently lightening up the winter days… (Pentax K200, SMC Pentax A 1:2 50mm, 12mm extension tube, Walimex ring flash)

A fluxgate magnetometer – a prestudy

Response (lower trace) of the toroidal fluxgate to a sine wave of about 7 V amplitude (upper trace, heavily distorted because of the limitations of the signal generator) in the presence of an external magnetic field..

Just a few days ago I read up about variations in the magnetic field of earth and how these can be used to detect northern lights. Since there have been sightings of northern lights quite recently even in major parts of Germany I became interested in the topic. A common type of magnetometer is based… Continue reading A fluxgate magnetometer – a prestudy

…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. I… Continue reading …another watt saved…