op-amp availability and Vensim alternative

[From Bill Powers (2004.02.17.1144 MST)]

Bruce Nevin (2003.02.17 12:19 EST) --

I noticed when I read this before Christmas that a google search on op-amp
turns up a large number of sources and resources.

Glad to know that Vensim is a convenient alternative.

Yes, there's nothing special about op-amps that can't be simulated. If you
want some, I have perhaps thirty or forty left after giving B. Williams a
dozen or so a few years ago (I bought 100 of them at a nice bulk price,
like 50 cents each). About the only thing you get from real op-amps is the
necessity of doing frequency stabilization, and burning your fingers with a
soldering iron.

Best,

Bill P.

[From Bruce Nevin (2003.02.17 12:19 EST)]

Was Re: Theory, generalization, model, simulation

Bill Powers (2003.12.21.0727 MST)--

···

At 07:54 AM 12/21/2003 -0700, Bill Powers wrote:

Bill Williams 20 December 2003 10:35 PM CST --

There are some really tricky issues involved in thinking about and in
writing a program that treats temporal relationships correctly. Learning
control theory with simple Op-Amp circuits avoids this problem.

I agree, but they're a little hard to come by nowadays,

I noticed when I read this before Christmas that a google search on op-amp
turns up a large number of sources and resources.

Glad to know that Vensim is a convenient alternative.

         /Bruce Nevin

[From Bill Williams 20 December 2004 3:00 PM CSG]

[ Bruce Nevin (2003.02.17 12:19 EST)] writes concerning the difficulties involved in obtaining electronomic parts.

It has been my experience that if you go to a distributor, or manufacture's
representative, tell them you ae working with students, show them a letterhead, and work to create a good impression, people will, at least some of the time, place a pesky order for a few parts.

Students ask me, why work with the actual devices, when there are simulation programs?

My answer is that I know how to plug wires into a bread-board, and to use a simulator I would have to learn how to use the commands.

Unfortunately, in the circumstance in which I find myself, neither I nor the students do either. There are much more pressing issues that demand a student's time-- such as passing the comprehensives.

Bill Williams