Also, you might consider using Mouser or Digikey for purchasing your electrical components rather than ebay. I think that you will find that the overall cost is lower and the quality level is higher. Ebay can be a great place for finding rare components (like 74141 or nixie) but is not the preferred place to shop for the normal stuff.
The 555 designs work well for a lot of people, but if there is no specific reason why you're using that design (other than that you have most of the parts already) then I you might consider switching to Mike's MC34063 mk1.5 design. I would not try the max1771 designs if you are not able to make the 555 design work. The max1771 is notoriously picky about layout. -Adam On Sat, Nov 19, 2011 at 1:27 PM, Nick <n...@desmith.net> wrote: > if the FET is smoking, it may be permanently on. Firstly, if you don't > mind me saying so, you are very new to all this and getting the > pinouts on FETs, ICs, transistors etc. wrong is easy to do. > > Secondly, inductors are not measured in Watts - lots of other things, > yes, Watts, no. They will have a saturation current - personally, that > inductor "looks" a bit small - a larger one (still 100uH but with a > higher current rating) might be better. > > Thirdly, I'd really check hard that your 555 is oscillating and on the > pin you expect - if its locked on, then that might explain why your > FET caught fire (it'd be shorting your input supply to ground through > the tiny inductor, which would then cook too). It happens... Check > every pin on the 555 is going where you expect. Check the feedback > transistor pinout is actually what you expect. Make no assumptions at > all about anything being above suspicion. > > Get another pair of eyes to check your wiring - its easy even for > experienced engineers to get "blind" to obvious mistakes (obvious to > others, that is). Get a second opinion, and let them check it from the > original schematic - don't let them assume anything. > > If you've never played with a 555 before (the world's most popular > IC), trying doing some simple stuff like flashing an LED at 1Hz (lots > of schematics out there for that) - boring maybe, but you'll learn an > awful lot... > > Cheers > > Nick > > -- > You received this message because you are subscribed to the Google Groups > "neonixie-l" group. > To post to this group, send an email to neonixie-l@googlegroups.com. > To unsubscribe from this group, send email to > neonixie-l+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/neonixie-l?hl=en-GB. > > -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To post to this group, send an email to neonixie-l@googlegroups.com. To unsubscribe from this group, send email to neonixie-l+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/neonixie-l?hl=en-GB.
