Hello Everyone,

I have long been wanting to reproduce an experiment or so similar to those that may have been used by Mr. Harold Stephen Black when he discovered Negative Feedback. I have not been able to pin point the exact kind of Vacuum Tube/Tubes/Op Amp setup he may have been working with. Would anyone have insight on which rocks I should be turning over? I have dug deeply into the history and papers of control theory via IEEE but most of the papers are a mathematical treaties on the topic rather than experimental ones. I know I could do it using solid state op amps but the geek inside of me wants to do it using vacuum tubes. I would appreciate any help or insight you may be able to provide.

Cheers,

Wess

 

I think it's likely that Bell Labs had proprietary vacuum tubes that Black was working with. They almost certainly had state-of-the-art tube prototyping and manufacturing capabilities.

 

I don't see why you need to use the exact device that Mr. Black used. Negative feedback can be demonstrated in many ways. Would you like to present a schematic and see what we can do with it?

 

Thanks for your reply #12. As I mentioned in my OP. I want to do this for fun. I am well aware that there are many ways to demonstrate it as I alluded to in my OP i.e. using OP AMPS and the like. I just wanted to try and recreate a little piece of history. I am on a hunt trying figure out what kinds of tubes were used so I can teach myself about them thus no schematic until then. Thanks for your time.

 

You can look up his original patent on Google - 2,102,671.
The tubes were all Western Electric company types:
265-E
245-A
7592-A
205-E
259-A
"tube of ordinary type"

As you can imagine in most patents, they leave things as general as possible so as not to limit future enforcement.

Now the only question is how these might correspond to "modern" tubes.
The search continues...

The history is very interesting.
Great question.

HERE is the Western Electric vacuum tube book that can be used for cross reference.

And look at THIS! You can buy a couple of vintage WE 274B tubes for a mere $2,025!!!!

 

Black's paper describing his invention is available here:

http://www.alcatel-lucent.com/bstj/vol13-1934/articles/bstj13-1-1.pdf

This paper has been made available in the public domain by Alcatel-Lucent.

There is a schematic diagram in the paper, but the individual vacuum tubes are not identified.

Edit:

Here's a paper that shows how important negative feedback was in the development of long distance carrier telephony:

http://www.alcatel-lucent.com/bstj/vol16-1937/articles/bstj16-1-1.pdf

 

Electrician: Both of your links failed when I tried to use them.

 

I just noticed myself that they aren't working now. I've been browsing their site for the last couple of hours; about ten minutes ago I started getting a 404 error.

I assume their site will come back on line again, tomorrow maybe?

 

It's working again, midnight PST.

 

Thank you everyone! It never occurred to me to search "old patents" on Google! That is great! OK I will do some studying of the new materials and probably come back with more questions. Oh wow! The Bell System Technical Journal! This is the main reference I have been working from trying to "Walk through History of Control Systems" http://www.amazon.com/Frequency-Res...ency+Response+methods+in+control+systems+IEEE