Posted by bob on October 21, 2013

Most of you are familiar with the electronics term feedback.  In an op-amp circuit, you can have positive or negative feedback.  Feedback can be delayed or filtered by various circuit components to create all kinds of interesting circuits and behavior.

A system with lots of positive feedback will have the tendency to slam up against the power supply rails, since a small change is reinforced by large system gain.  The system achieves hysteresis as it can now take a bigger input change to move the output in the other direction.  You are turning the op-amp into a comparator in these systems.  The output looks like a square wave, slamming up against the rails in both directions.

A system with too much negative feedback can become unresponsive or the output might be severely distorted if there is a lot of signal shaping in the feedback path.

Our real world lives include positive and negative feedback.  For example, when your boss calls you in for your annual performance or salary review, you are getting one kind of feedback.  When your friends make comments on your latest Facebook page, you are getting a different kind of feedback.  Both will affect the behavior of your personal system.

When my book sells to readers through retailers like Amazon or Barnes and Noble, the feedback mechanism has a long delay and some filtering.  But there is a fairly simple cure and this is where you individually come into the picture.  If you purchased or borrowed An Engineer’s Guide to Solving Problems and have read some or all of it, I really appreciate hearing your honest feedback.  No, this is not an invitation for meaningless nastiness or abuse, but this is also not an invitation for empty praise.

The only way I can improve is to hear honest statements about what you don’t like (and what you do like) about my writing.  That can include the things you find on this blog.

It is easy to reach me.  You can go to the Contact Page or simply send me an email at the address shown below.  It is shown as an image to keep spam robots from filling my inbox, but you will only need to type it once.  Most email clients will save it as a future contact.

I cannot promise to reply to every incoming email, but I will make every possible effort to read them all.  Responses might be individual, collective, or published here.

So, what are you thinking?

bob at ...