OT: Howland Current Source/Pump

Hello Ban,

A moisture problem? Got to fix that...

Regards, Joerg

Paperback, page 14 (mine is ©1984)

...Jim Thompson

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|  James E.Thompson, P.E.                           |    mens     |
|  Analog Innovations, Inc.                         |     et      |
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Can anyone point me to the original paper for the Howland Current Source/Pump?

Thanks!

...Jim Thompson On current and earlier literature references to Howland Current Source/Pump circuits:

1) There is an excellent discussion on pages 189 - 195 of Tom Frederiksen's op amp book, Intuitive IC Op Amps (National Semiconductor, 1984). Frederiksen analyzes both the 4 and 5-resistor forms of the circuit. This is very good stuff, indeed. In his bibliography, he mentions the GAP/R apps manual from 1966. Although Frederiksen doesn?t specifically mention it, Bob Pease encouraged and influenced what did appear within his fine narrative. (RAP > WGJ email, March 2006). Pease calls Frederiksen?s book ?a little classic in its own right?, a point with which I?d agree. He also contributed a Foreword to the book. 2) From my own IC Op Amp Cookbook 3d Ed. Ch. 4 References, pages 218 ? 223, there are at least a couple of key references to Howland type circuits. a. The first is Tim Henry?s "Analysis and Design of the Op Amp Current Source", Application Note AN-587, October 1973, Motorola Semiconductor Products, Inc., Phoenix, AZ. Note: archival copies of older Motorola Semiconductor app notes are available from Freescale Semiconductor. To download the Henry app note go to: b. There is also the 1965 GAP/R applications manual, now available online as per the URL indicated by Dan Sheingold, below. c. Dan Sheingold's GAP/R Lightning Empiricist article from the January 1964 issue sheds light on the Howland circuit, and actually, is the first public mention of it. This article is available online at: 3) Dan Sheingold summarized the history of the Howland circuit from his days at GAP/R (DHS > WGJ email, Feb. 2006) as follows: Walt:

The "Howland circuit" was originally described in a personal note (ca

1961(?)) from Brad Howland (then at MIT) to George Philbrick, who gave it that name.

A form of the circuit can be found in print in the Philbrick "Applications Manual..." (page 66, module III.6)

Adaptations of it appear in modules III.7 and III.9.

Bob Pease has done some further development on the circuit, with improvements to stability, range, etc.

Best regards,

Dan There have been folks looking for the original Howland paper, even posting lists here of Bradford Howland references, and speculating on which one had the discussion re the circuit. Hopefully the above will put this to rest. The first public appearances were within GAP/R literature items, in 1964 and 1965, as above. Walt Jung

Thanks. Much appreciated.

Robert