Sunday, July 13, 2008

Week 4: Intro to Oscillators

Whole lotta beepin' goin' on at this week's Intro to Oscillators session. For folks that missed it, instructions are posted as a web page, since some of you were having trouble with Word docs... follow along at home and we'll do some more next week.

A few suggestions, based on troubleshooting we did yesterday:

  • Use the thin solid wire on the breadboard, not the thicker stranded stuff.
  • Build one oscillator at a time, and get it to work, before moving on to the next one.
  • If some oscillators work but one won't, it could be the chip. I have spare chips, try using one of the other inverters (like pins 9 and 8, on the other side of the chip) in the meantime.
  • Make sure your components are seated all they way down on the breadboard--the IC has pretty stubby legs, so sometimes it looks like it's plugged in when it ain't.
  • Trim your component leads... when they're all gangly and sticking up, they can short out or lean over into their neighbors. For the resistors going into adjacent holes, fold one lead over so they can stand up vertically:
  • You don't have to be neat, but it's harder to troubleshoot if you're not. I'm just sayin'. Anybody that's seen the lab knows I'm not a neat person... but something like this is likely to work, and if it doesn't it'll be easier to figure out why:

I'm working on pulling together some resource and reference links, for things like resistor codes and suppliers. Let me know if you have suggestions.


Sam Harmon said...

I wrote a few supplier suggestions on my blog. Hack A Day also has a good resource on suppliers here (the comments are almost as good as the post itself).

fluxmonk said...

yes... in the second pic, the 3rd oscillator output (green wire) is going to the wrong hole for the mixer resistor... should be one hole to the left, row 40. see?