Category: Electronics

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…

Teaching an old bug new tricks

The prototype unit on perfboard.

The 78S40 is not one of the most modern switching regulators, together with its small brother the MC34063 it dates back to the 1990’s. It differs from the 34063 by having an additional, uncommitted operational amplifier inside its 16-pin package. There are many application notes available, since both chips are manufactured by several companies. There… Continue reading Teaching an old bug new tricks

Do they know what they do?

Standard LED driver

As you can read in my earlier posts I have become quite attached to the AVR microcontrollers from Atmel. We also use these microcontrollers in projects with our students at Uppsala University. Probably one of the widest spread development tools for AVR controllers is the original STK500 starter kit from Atmel, which in principle supports… Continue reading Do they know what they do?

The new Digikey catalog is here!

2011 Digikey's new catalog

Today I got the new Digikey catalog delivered at the university. It must be the season, during recent weeks also Elfa (you remember: the company which delivers cable by the metre…) and RS-Components have mailed their new paper catalogs. I still prefer paper catalogs in spite of their environmental impact, because there is simply no… Continue reading The new Digikey catalog is here!