Design

SMT by hand
Any have any tips for QFN packages by hand without a stencil? The main problem is that there seems to be no easy way to check/fix to make sure the leads are soldered since they are completely under the package. I was thinking of using puting solder paste on the pads by hand and attempting to properly align the ... 15 Jan 2010 06:04

Looking for photo frame that does GIF...
*animated* GIF. Anybody know one that does - some say GIF on the box/in the specs, but buying/trying/returning is a slow way to find one that works. Yes, I know there would be other solutions ("program a pic") but what I want is a box I can get a dozen of cheap, shove an sd card in, and have it work. ... 27 Dec 2009 08:41

When are ferrite beads the most approproate component to use?
I've never found an application where a I felt a ferrite bead as head ahd shoulders over a resistor or some other means filtering the signal. Most of the develpments Im involved with are power conversion and data acquisition (ADCs and DSPS)from various sensors. For lowish frequency stuff (say sub-10MHz) in wh... 6 Jan 2010 09:14

Idiots
http://www.nytimes.com/2009/12/27/us/27security.html So a guy tried to detonate a bomb during the last hour of a flight. The TSA morons thus conclude that all terrorists detonate their bombs in the last hour, so make it illegal to get out of your seat during those 60 minutes. They are clearly assuming that th... 6 Jan 2010 18:48

HT Relay
I am trying to select a relay for a delayed HT switch (which will also discharge the HT when off). Most relays I can find have contacts rated at 250VAC which translates into a peak of about 350V. However, data is scarce on what dc voltage these relays can switch. So far I have found only one that gives a dc cur... 28 Dec 2009 20:42

UV LED On Toenail Fugus
http://en.wikipedia.org/wiki/UV_light 'Certain fungal growths under the toenail can be treated using a specific wavelength of UV delivered from a high power LED (light emitting diode) and can be safer than traditional systemic drugs.' '300-320 nm: Light therapy in medicine' Nail fungal species: http://en.wiki... 28 Dec 2009 01:00

Driving a PNP with a 555
I want to use a classic 555 timer IC to drive the base of a PNP transistor through a resistor, the emitter of the transistor being tied to the 555's Vcc. The 555 datasheet gives a graph for the high-state output voltage vs. sourcing current, but not when the load is tied to Vcc. Vcc -----... 28 Dec 2009 08:34

Top ten analog engineers
http://www.analog-europe.com/212700488;jsessionid=2EYNK2XDSG2HZQE1GHOSKHWATMY32JVN?pgno=1 George Philbrick Bernard Gordon Jim Solomon Barrie Gilbert Bob J. Widlar Bob Pease Jim Williams Dennis Monticelli Tom Hornak pity about Alan Dower Blumlein apparently the fact that he never worked in the USA me... 28 Dec 2009 05:18

Simple isolated mosfet driver
Is it possible to drive the gate of a high side n-ch mosfet using an optocoupler to isolate and float the gate w.r.t to the source and still be effective? I want to continuously control the gate of a high side n-ch mosfet to prove a variable resistance for a high voltage load. G = Gate, S = Source, D = Dr... 23 Dec 2009 13:52

feedback and stability
I built a voltage regulator for an old truck I own. The circuit uses a voltage controlled oscillator with a square wave output to drive the gate of a mosfet that controls the alternator's field. The voltage regulation feedback loop uses a voltage divider from the alternator output/vehicle battery, connected t... 3 Jan 2010 22:40