Recent content by BRUCE A RATCLIFFE

  1. B

    My variable speed drill switches turn into ON/OFF switches :-(

    I tried the 0.1 uF (ceramic) cap in series with the speaker, but heard no click on the CONTROL switch. Perhaps a cap that small doesn't let ecnough current through to wiggle the speaker cone? I next tried a ~100uF cap. Silence. Perhaps the surge was so brief the cap could just be filling...
  2. B

    My variable speed drill switches turn into ON/OFF switches :-(

    Interesting Idea, Balancore. I will brave the 110F heat on my bike to head down to my classroom to try it with the speaker. I'm assuming that if I can hear a click, it will be a quieter click when I test the FWBR-equipped switch.
  3. B

    Motivating high school Physics students with Popcorn Physics

    TOO funny, Charles! I was proud of my solution, featuring units analysis AND fractions--the terror of my students. And then I see your oh-so-simple solution. Bruce
  4. B

    My variable speed drill switches turn into ON/OFF switches :-(

    I've built the prototype but now realize a problem: Does it protect my switch? I thought I'd simply connect an oscilloscope across the motor and check for a spike on the trace, but can see nothing. I'm embarrassed to say I never bothered learning much about how to use oscilloscopes. Perhaps...
  5. B

    Motivating high school Physics students with Popcorn Physics

    I'm not sure if this is what you call an elegant solution. Maybe cumbersome would be a better descriptor. But here's my solution: It is a rate problem. Bob: 1 bag/20 min Mary: 1 bag/30 minutes. To add fractions you need a common denominator: Bob: 1bag/20 min = 3 bag/60 min Mary: 1 bag/30...
  6. B

    Motivating high school Physics students with Popcorn Physics

    How did you find PF?: Quiet Desparation prompted me to search for "Electronic forums" I've been teaching physics for forty five years (quadruple alliteration : ) Though I would dearly love to teach a rigorous, math-based course, if I did so, my clientele would be lost, bored and gone. My...
  7. B

    My variable speed drill switches turn into ON/OFF switches :-(

    Thanks for your quick reply. The FWBR-to-motor distance is ~3 inches. For that distance, would 16 or 18 gauge stranded allow enough current during the voltage spike? Of course, the actual motors are a couple of feet away, along a 12 AWG stranded wire. The motor in the phrase FWBR-to-"motor"...
  8. B

    My variable speed drill switches turn into ON/OFF switches :-(

    This is great. After having soldered the connections for, oh, 15 years, your advice has prompted me to do a redesign that is much simpler and, I think, more elegant. I'll show you the BEFORE and AFTER pictures when I get a prototype completed. I do have one more question. What gauge wire...
Back
Top