Other Web Sites
Related to HP History
updated Sept. 30, 2007
The links listed below are to other web sites related to HP
History. Some of the web links are moving targets. I check
these from time to time and find some of them dead only because
of a subtle change in the URL when a website was reorganized.
Here are some direct internal links to the HP web
facts and online museum This sub page on the HP web
site is a must visit! There are lots of pictures, facts, and
stories of vintage equipment and company history. Plan on
spending some time here as there is a lot to see. I hope this
site will be expanded to include more classic vintage equipment
as the site only displays a tiny fraction of what was made.
One sub page is devoted to the
history of the HP200A and has quite a bit of information I
have not seen anywhere else. The page was posted in Jan. 2002
which was the 60th anniversary year of the
patent William Hewlett received for the audio oscillator in
1942. This particular oscillator is supposedly the first
one Bill assembled for his master's thesis at Stanford.
That unit would have been for demonstration and not for
production. There are several interesting things to note
The last paragraph has a subtle error concerning the
HP200CD (the best known of all the HP oscillators) as a replacement for the
HP200A. The HP200AB was the direct replacement for the HP200A and
HP200B in 1952 (not 1953) and was an improved version covering the combined
frequency span from 20 Hz to 40 kHz and could deliver about one watt of power to
a 600 ohm load. Similarly, the HP200CD replaced the HP200C and HP200D also in
1952 but with an improvement in the output power -- approximately one watt as
compared to only about 100 milliwatts for the C and D units and also a
much wider frequency range. The HP200CD had a frequency range from 5 Hz to
600 kHz as compared to the 7 Hz to 200 kHz covered by the C and D
units. The HP200CD (designed by Barney Oliver) achieved the wide frequency
range by using a push-pull version of the Hewlett design and also used two
output transformers -- one for low frequency and one for high frequency.
With its frequency range wider than covered by the A, B, C, and D units the
HP200CD effectively replaced them all. The HP200AB was last listed in the HP1975
catalog. The HP200CD was last listed in the HP1985 catalog. This 33 year run of
a product is truly remarkable. All of these oscillators were based on same
concept developed by Mr. Hewlett in the late 1930s. They were all built with
vacuum tubes and used a lamp filament as the amplitude stabilizing element. So
an HP200CD of 1985, the last HP oscillator based on vacuum tubes and to use a
lamp filament for amplitude regulation, is very closely related to the original
HP200A of 1939. The total manufacturing run of this concept then extends from
1939 to 1985, or 46 years!
- The variable capacitor has a right angle drive. That
was not the case for the production 200A, B, C, and D units --
they were straight shaft only.
- There are only four vacuum tubes. The production
versions had five tubes. However, what is identified as the
light bulb may be a tube instead. The picture has too low
resolution to be sure.
- There is only a power transformer. There is no audio
output transformer as was on production units. This might
be consistent with only four tubes with only one tube used for
the output amplifier.
- Although the 1939 schematic shown on the page has such low
resolution that it is nearly impossible to read but I can make
out that there are five tubes and an audio output transformer
shown. But that is a later version of the original thesis
- The tuning dial shown appears to be from a production 200B
- The red and black output jacks are not the originals -- those
would have probably been lost/worn over the years and would
have been replaced.
Here are some direct internal links to the Agilent web
Bill Hewlett biography
Dave Packard biography
Company time line
Agilent Technologies and Communications: Six Decades of
Measurement Solutions This is an excellent
35 page article about many of the classic pieces of equipment developed at
HP. It has a lot of history and is required reading. There
are a few errors that should be noted as follows. I was not
looking for errors but these stood out to me as I am familiar with
- The opening picture showing David Packard
(standing) and William Hewlett (with slide rule) in the garage is mirror
imaged. Proof that the picture is mirrored is obvious by looking at the audio
oscillators and noting that the output jacks appear on the left instead of
their correct place on the right. The same picture on the HP site above is
- On page 18 the upper frequency limit of the HP500A
frequency meter should be 50 kHz instead of 100 kHz. I own an HP500A and am
quite familiar with it.
- On page 20 the model number of the VHF generator in
the picture should be HP8640B. This is a simple transposition error in the
caption. I own one of these units so I am quite familiar with it.
- On page 22 the year HP entered the oscilloscope
market should be 1956 instead of 1958 (product development actually began in
1955). The March, 1956 (Volume 7, #7) issue of the Hewlett-Packard Journal
describes the introduction of the HP130A oscilloscope which had a 300 kHz
bandwidth. The April, 1956 (Volume 7, #8) issue of the Hewlett-Packard Journal
describes the introduction of the HP150A oscilloscope which had a 10 MHz
- On page 28 the description of the HP4815A impedance meter
should show an upper frequency limit of 108 MHz instead of 500
MHz. I own an HP4815A and am quite familiar with it.
Other web sites with a variety of information:
Some of these are deep links and others may only be available
temporarily. If the web page is not found, try backing up by
deleting pages from the end until you connect to something. A
reorganization of the web site may have changed the address.
http://www.slack.com/elec.html This is
an excellent site of general interest concerning electronic
test equipment. It is a site of many links to other online
museums of test equipment, online test equipment manuals,
application notes and other related information. In
addition to information on HP equipment there are links for
Tektronix, Fluke, General Radio, and others.
http://www.antiqueairwaves.com/ This is a great site if you are looking for information about old
radios and electronics. There are numerous links here to
just about everything involving old electronics. You could
spend hours looking at all this stuff. A related site by
the same owner is
http://www.stevenjohnson.com/ and you can find even more
information including schematic diagrams, etc.
"This site is a free non-profit repository of materials from
GAP/R George A. Philbrick Researches, the company that launched
the commercial use of the Operational Amplifier in 1952."
(quoted from the site)
http://home.comcast.net/~cbmcg/Panadaptors.html This site has some very interesting history about the very
first spectrum analyzers ever made. The company that made
them beginning in the 1930s was the Panoramic Radio
Corporation. This is some very rare history that all should
http://www.jvgavila.com This is a site in Spain and
features a personal museum and information about HP and a variety
of other equipment manufactures.
This link has pictures and stories of famous garages including
Bill and Dave's.
This article is about the move to use just HP instead of
Hewlett-Packard after the Agilent spin-off.
A few articles concerning the HP-Compaq merger
An interesting article written during the controversy over the
Compaq merger. I voted my HP shares against the merger as
it made no sense to me. I had owned Compaq stock for many
years and dumped them at a huge profit in 1999 when it looked
that Compaq had no place to go but down. I was right.
http://www.forbes.com/2002/02/14/0214malone.html This is a very good article by Michael S. Malone concerning
the HP Compaq merger. Click on the skip the welcome screen
in the upper right.
An obscure application of the Wein bridge
The following two links are an interesting history of the late
1930s concerning an application of the lamp stabilized Wein
bridge oscillator. The author tries to make a case
that there was a possible association between Mr.
Hewlett and an individual named Mr. Beam Ray. There are a
number of historical connections that if true are quite
interesting. The application of the electrotherapy machine
discussed in the two articles is a bit on the bizarre by
today's standards but people actually believed in this at
Links to other web pages on this site
http://www.kennethkuhn.com/hpmuseum This link takes you to
the main HP Museum page.
http://www.kennethkuhn.com This link
takes you to the main page of my personal web site where you can
access a variety of information.