History of Keithley electrometers

[Anders Petersson]

Having just bought a Keithley 6514, I wanted to learn how this line of specialty instruments has evolved over time. Has anyone published a summary?

Here's my stab at piecing together the history. The sources for the release dates are in parentheses; mostly the oldest print history date of the manuals. As none of this is officially confirmed, I've marked all the dates with a question mark:
602 -  1975? https://download.tek.com/manual/29111C(Model602).pdf
610B - 1964? (From the schematics in http://bama.edebris.com/download/keithley/610b/MFG_KEITHLEY_610B_BR.pdf)
614 - 1981? (srb1954 says the earliest dates in the manual is 9-8-81, and SilverSolder confirms manual copyright 1981)
616 - 1975? (https://download.tek.com/manual/28039I(Model616).pdf)
617 - 1984? (https://download.tek.com/manual/617_901_01G.pdf)
619 - 1981? http://bama.edebris.com/manuals/keithley/619/
6512 - 1994? https://doc.xdevs.com/docs/Keithley/6512/, https://doc.xdevs.com/docs/Keithley/6512/photo/
6514 - 1998??
6517 - 1994 https://xdevs.com/doc/Keithley/6517/6517_900_01D.pdf
6517A - 1996 (https://www.aps.anl.gov/files/APS-Uploads/DET/Detector-Pool/Electronics/Meters/6517A_Users_Manual.pdf)
6517B - Some time 1997-2014 (from jjoonathan comment, citing davesherman74)
 
Picoammeter
6485 / 6487 - 2002? - https://download.tek.com/manual/6487-901-01(B-Mar2011)(Ref).pdf

SMU
6430 Sub-Femtoamp Remote SourceMeter

The dates can be questionable. For example, if judging from the manual print history, 6514 came in 1998 and 6517A came in 1996. I can't believe the superior 6517 was released before 6514 so the manual print history is probably not the way to learn this. Does someone know the facts?

For reference, there's a support forum at https://forum.tek.com/viewforum.php?f=39

It's interesting to see the performance progression, for example the 1-year accuracy of the most sensitive amps range:
617: 1.6% + 66 counts (range 2 pA, resolution 100 aA)
6514: 1% + 30 counts (range 20 pA, resolution 100 aA)
6517B: 1% + 30 counts (range 20 pA, resolution 100 aA)

Others are welcome to correct my mistakes and fill in more details!

EDITS: Updated 3 times with new/corrected information.

[KK6IL]

Ive got a Keithley 616. 9th printing of the manual says Copyright 1975.

[jjoonathan]

Dave's DMM7510 teardown has a relevant comment:

Nicely done.  Former Keithley engineer, 1997-2014, just before the model 7510 was released.  I can say that the Actel FPGA at 20:00 is indeed the integrating A/D.  I was the lead firmware engineer for the 6517B electrometer and that A/D was developed for both.  You are correct, it's a custom design, and it's a variation of a dual-slope A/D converter.  I had to chuckle at the "evil Danaher" comment, part of the reason I left.  It just wasn't the same company I started with.  I was among the last few new hires who got to meet Mr. Joseph F. Keithley, the founder.

[Anders Petersson]

Ive got a Keithley 616. 9th printing of the manual says Copyright 1975.

Dave's DMM7510 teardown has a relevant comment:

Nicely done.  Former Keithley engineer, 1997-2014, just before the model 7510 was released.  [...] I was the lead firmware engineer for the 6517B electrometer [...]

Thanks to both, added to the initial post.

[srb1954]

I've got a 614. Looking at some of the chips used in it it I would think the design would started in the late 1970's.

The earliest date I can see on the drawings in the manual is 9-8-81 so I would guess it was released sometime late in 1981

[graybeard]

I met Joe Keithley in 1983.  I was a new graduate student working for Kurt Lehovec at USC.   He had brought a pre-production 617 with him for Professor Lehovec to try.

[SilverSolder]

I've got a 614. Looking at some of the chips used in it it I would think the design would started in the late 1970's.

The earliest date I can see on the drawings in the manual is 9-8-81 so I would guess it was released sometime late in 1981

I also have a 614, the manual is copyright 1981, fourth printing in July 1991 (I assume this is the newest/most recent version of the manual but I am not sure).  So at least a 10 year run for this model?

[Anders Petersson]

FWIW, info from SilverSolder and srb1954 is added to the initial post.
The post from graybeard confirms existing info.
There's some long experience on this forum!

[MegaVolt]

Perhaps it makes sense to add models:
6430, 6485, 6487

[HighVoltage]

Interesting thread!
Subscribed!

Maybe you can add the official original list price next to the instruments.
As far as I know, the 6517B is still in production with a list price of €9,200  in Europe.

[Anders Petersson]

Maybe you can add the official original list price next to the instruments.
As far as I know, the 6517B is still in production with a list price of €9,200  in Europe.

I can make the post into a HTML table with various info. But I don't know any of this myself so please post any info you have or can dig up that is suitable for a compact table. 6517B (and apparently 6514) are in production so those list prices are easy, but I'd like to see if we know pricing for some older models before adding a column for it.

I guess I can add a section for SMUs and picoammeter too.

[KeepItSimpleStupid]

I think the 236, 237 and 238 series SMU's should be added.

There's the stand-alone pico-ammeters (Keithley 480, 485)
There may have been some Analog Pico ammeters

The 619 was wierd.   The analog out was wierd.

I discovered a bug in the 617 because it was destroying our devices when it switched ranges,  There were 200 V spikes at the inputs.  Keithley was really surprised when they confirmed it and immediately created an external solution that only worked in measure voltage mode until they developed a fix for the instruments.

That wasn't the case with Apple.  I found that sending an email with ATH$ in the body of the email would hang-up the modem in the iBook every time over dial-up.  They didn't have the courtesy to test it.  I suffered for at least 9 months until they fixed it.

1980+  Fluke and HP and Tektronix were Kings.

[HighVoltage]

I discovered a bug in the 617 because it was destroying our devices when it switched ranges,  There were 200 V spikes at the inputs.  Keithley was really surprised when they confirmed it and immediately created an external solution that only worked in measure voltage mode until they developed a fix for the instruments.

Interesting!
When was this, if you remember?
Must have been the first 617 delivered because I never saw this bug on any 617

[KeepItSimpleStupid]

I know the instrument was recently introduced and it really wasn't good enough for what we wanted for two reasons.

1) The max current of 20 mA
2) the voltage resolution

1) We really would have liked 100 mA.  There was also a 100 ohm protection resistor that I quickly blew. That was a surprise too.
2) Ended up using a Keithley 230 voltage source as well, BUT I ended up using the sense leads of the 230 to compensate for the resistor.

The application was research grade solar cells, so 5V could possibly damage them.  The system was mainly purchased to do I-V-T measurements to get activation energy and conductivity of thin films of silicon.

[Smokey]

I think these are the Keithley Low Level Measurements Handbooks release dates, with what electrometers are mentioned:

1st Ed = 1984 (See Below)
2nd Ed = ?? (See Below)
3rd Ed = ?? (See Below)
4th Ed = 1993

5th Ed = 1998
https://archive.org/details/lowlevelmeasurem01keit
(Section 5.3 Lists 610C, 614, 617, 642, 6512, 6517)

6th Ed = 2004
https://pearl-hifi.com/06_Lit_Archive/15_Mfrs_Publications/Keithley/6th_Low-level_Measurements.pdf
(Section 5.3 Lists only 6514, 6517A)

7th Ed = 2013
https://download.tek.com/document/LowLevelHandbook_7Ed.pdf
(Section 5.3 Lists only 6514, 6517B)

[Brad O]

I think these are the Keithley Low Level Measurements Handbooks release dates, with what electrometers are mentioned:

You have some of the early ones wrong, here are the Low Level Handbook publish dates:
1st Ed.  - 1972
2nd Ed. - 1977
3rd Ed.  - 1984
4th Ed.  - 1993
5th Ed.  - 1998
6th Ed.  - 2004
7th Ed.  - 2013

The first 2 editions were called "Electrometer Measurements", then it was called "Low Level Measurements", Handbook was added with the 7th edition. For fun, here's marketing photo from the 1st ed. It started as a way to reduce questions to the Apps team on how to use an electrometer, then other instruments and discussions were gradually added. Quite a bit of 7th edition is directly from the 1st though still.

Some other details missing from this thread: the first Keithley electrometer was the model 200 released in 1951. That was followed by the 200A, 210, 200B, 410, 411, 412, 413A, and then the 610. There was also a 600A and 600B. I sadly don't have many details on those early instruments, this list comes from a company retrospective Mr. Keithley wrote in 1971, I could post the whole thing if people are interested.
Also there was the 605 negative capacitance electrometer (released 1967), whose manual is still available on tek.com: https://download.tek.com/manual/605A(Model605).pdf. I'm also attaching a pre-edit photo I have from its marketing shoot, you can see this same setup in the manual. It features a Tek 561A Scope that we still have in the office. I don't think Mr. Keithley considered the 605 part of the main electrometer line though. 

[factory]

Also not in this thread is the 615 digital electrometer, probably not many have survived, this one was once a Keithley demonstrator, serial number is +1 above the one pictured in the manual.





And there is another in my collection, the 445 autoranging digital picoammeter.



IanScottJohnson has done a video on the 440 digital picoammeter, the last of the trio of early digital instruments that I know of (not including DMMs).



David