Who invented the Mu Follower?

Subject says it all really. I found the White Follower patent from 1943 but all I can find out about the origins of the Mu Follower is that Alan Kimmel 're-discovered' it in 1993. So who actually invented it?

Cheers

Ian

ruffrecords said:

Subject says it all really. I found the White Follower patent from 1943 but all I can find out about the origins of the Mu Follower is that Alan Kimmel 're-discovered' it in 1993. So who actually invented it?

Cheers

Ian

Click to expand...

Please look at US patent Nr 6.265.938 there:

http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2&f=G&l=50&co1=AND&d=PTXT&s1=6265938&OS=6265938&RS=6265938

It all depends if you're looking for this particular circuit topology or the generic name "mu-follower" which can be copyrighted but not patended. (like the "vari-mu" term)

I remember I've seen a very similar circuit in an old issue of ELECTRONICS (Mc Graw-Hill publications) from the fifties but it was not called a "mu-follower" then and used in some industrial or military type pulse drive circuit. (IIRC)
Or you may also ask Mr TDP and he will certainly tell you HE is the sole inventor of this circuit...

HI,

Yes, I am aware of that patent and have researched the ones it cites and ones cited by those too and still no sign of the straight mu-follower itself. The patent you mention does mention the mu-follower but gives no clue as to who invented it. I have been told it may have been described in an old Wireless World so I am pursuing that route too.

I have found what appears to be a patent for the SRPP but nothing that resembles the mu-follower. As you say, I am sure it was not called the mu-follower at the time it was invented.

Cheers

Ian

Hi Ian

Did Kimmel himself not invent it? I have an article of his from Glass Audio & I thought he did the groundwork himself.

Regards
Peter

peterc said:

Hi Ian

Did Kimmel himself not invent it? I have an article of his from Glass Audio & I thought he did the groundwork himself.

Regards
Peter

Click to expand...

No, I have been in contact with him and after his article in Glass Audio was published someone told him about an article in Radio and Electronic Engineer in 1958 entitled 'Bootstrap Circuit Technique' that shows it. I have obtained a copy from my local library and it does indeed show the exact circuit of a mu follower although it makes no claim to have invented it. In a section entitled 'Current Operated Bootstrap Valve Circuits' and a subheading 'Methods of Coupling' it shows four distinct arrangements 'according as the grid and cathode of the bootstrapped load valve are a.c. or d.c. coupled to the anode circuit of the driver'. The second, a.c coupling to grid and d.c. coupling to cathode, is the mu follower. The first, with dc and dc coupling is the SRPP. The article has lots of references but not one to the section containing the mu follower.

Cheers

Ian

Ian, is this you asking Jack ?

http://www.muzique.com/news/mu-follower-history/

Did you get any further with it ?

Marty.