Finding a pair of 2.2k resistors with identical values (2.19 on my meter) was easy... found two matches in the first five tests on a string of 100 resistors. Those go in and replace the earlier 100k pair at the top of the breadboard -- the chapter recommends trimming them down (the leads) so that they are less susceptible to electromagnetic interference, so I did just that... and on the 100k pair.
|Notice anything missing?|
Once that correction was made, I started seeing the results I wanted. Charles wasn't kidding when he says there's a point in the middle where the voltage jumps fast from negative to positive. Turning the 1k trimmer (I couldn't find my 5k) allowed me to watch the voltage go back and forth between positive and negative. now I've just got to figure out why the high end voltage is +4 and the low end is around -2.6. Probably something with the resistor pairs and them still having a slight variation in value... maybe?
Up next, I'll be dealing with negative feedback as opposed to the earlier experiment that used positive feedback. The circuit is almost identical, but Figure 11-4 has a few extras inserted -- a 10k and 1M resistor.
Video for Experiment 11 Part 1 is below...