Joshua C. Johnson:
Documentation for Analog
in this document, Mr. Johnson describes the design process and the
actual implementation of an analog computer together with some
introductory example problems, ca. 1.6 MB.
Zur Steuerung von Analogrechenschaltungen, Elektronische
Rechenanlagen, 8 (1966), Heft 5, S. 219-225 (thanks to
Rainer Glaschick for the scan and to DeGruyter Publishing for
their permission to offer this for download), ca. 1.4 MB
Entwicklungstendenzen im hybriden Rechnen, Elektronische
Rechenanlagen, 10 (1968), Heft 1., S. 11-17 (thanks to
Rainer Glaschick for the scan and to DeGruyter Publishing for
their permission to offer this for download), ca. 1.5 MB
What is a Hybrid Computer
and Why - publication detailing on the hybrid computer
installation at the Control Engineering Department of Cambridge
University (thanks to Matthew Butler for this document), ca.
Thanks to Rainer Glaschick, we now have a second version of the
manual for the EA-22,
ca. 2.4 MB.
Several new pictures in the
impressions section (EAI 380,
"General Purpose Simulator" used during the Saturn V-development, an
analog computer used for lunar landing simulations, and two pictures of
the EAI Starlight).
The introduction page now contains a
link to a book about analog computers as well as an interesting
chart showing how often the phrase "analog computer" was mentioned in
books in the last 100 years. In addition to that it now contains
a list of links to seven Youtube videos showing the operating
principles of mechanical analog fire control computers. It also
has been extended with a link to a newly developed harmonic analyzer
which is featured in Make! :-)
The impressions page has been extended
with a lot of pictures showing several EAI-231R(V) installations
(most notably the installation at the DLR in Germany), an EAI PACE
16-31R, an EAI TR-48 with a PDP11 and Udo Knorrs so called
"Fahrdiagraph" which is a mechanical differentical analyzer with
feedback that even predates the machines developed by Vannevar Bush.
Mr. Arno Jacobs developed a symbol library for the well known
layout editor EAGLE which
contains all symbols necessary to draw analog computer setups.
The ZIP-file contains
the library files as well as an example drawing showing a
I would like to thank Mr. Jacobs cordially for this library and
his permission to make it available at the analog computer museum.
Dr. Ralf Bülow found an interesting patent describing a completely
analog golf simulator -
a must read. :-)
I created a short video (about 5 minutes) showing the generation of a
Joukowski airfoil and the simulation of flow lines around this profile.
This video can be seen here:
A two part video film which shows the simulation of a somewhat more
complex system, a two-mass-system representing a simple car suspension
system. Especially interesting is the online grafic display which works
purely analog and shows the moving road, car wheel set and the car
frame (part 1
and part 2):
Yesterday I completed a short video clip demonstrating the use of an
electronic analog computer for simulating a simple mechanical system.
This 9 minute clip can be seen here:
EAI Maintenance Pocket
Guide - this small booklet (13 MB!) contains a wealth of
information helping the field engineering during repairs of EAI
analog computers. The most important part (at least for me) is
the section describing the integrated circuits used and the
list with transistor replacement types.
During the last couple of days I built the small analog computer
designed by Dr. Vogel and documented my progress with quite some
pictures and some remarks concerning necessary changes which were
necessary since I could not get hold of some special parts. The
description of this project may be found
developed a small electronic analog computer which is described on
his web page which is now linked to from the
Since my conversion of Dr. Vogel's original Word documents describing
his truly wonderful homebrew analog computer
to PDF was erroneous and deleted the first page of the schematics,
the two page schematics of his computer can be found
here for download.
The peoples page now contains a link to
and his outstanding
which brings true analog computer feeling to a modern UNIX system.
In 1977 Dr. Vogel completed his dissertation about a genuine new
resolver design without complicated diode networks. This is a very
interesting approach and his thesis contains detailed schematics of
his new resolver design. The thesis can be found
here (about 17 MB!).
A couple of days ago I setup a simple circuit to display or plot
the well known Lorenz attractor
using a Telefunken RA 770
EAI 3440 DATAPLOTTER -
a publication describing the 3440 DATAPLOTTER (about 1.6 MB).
EAI HYDAC - a truly wonderful
six page publication describing the then new EAI HYDAC 2000 system
with wonderful pictures of the system (about 1.3 MB). In addition
to this there is a
letter from EAI to its
customers introducing the HYDAC system (in German, 162 kB).
EAI MICROSTORE Model
2.395 - a product information release introducing the PACE
MICROSTORE, a high-speed tracking, storage and switching device for
the EAI 231R series of analog computers (about 1 MB).
EAI Products and
Services - a short publication covering the main products and
services offerend by EAI (about 2.1 MB).
Dr. F. Vogel wrote a wonderful introduction to
(in German) as well as a detailed description of his homebrew
(in German). I am grateful for his work and his offer to make his
writings available here.
Concept for Analog Computers - this was prepared for the
George C. Marshall Space Flight Center, NASA in 1968 when they
requested a study to be performed by EAI whether some form of
automatic programming was possible for analog computers.
Computing At Lockheed - a truly wonderful brochure showing
the incredibly large hybrid computing facility in use a Lockheed
in the late 1960s. This system is the result of the request for
proposal shown above and consisted of four Comcor Ci5000
analog computers coupled to a Control Data 6400 system. The PDF
file is about 2.5 MB large.
Thanks to my wife Rikka you can now download a 34 MB
PDF-file describing a school analog computer made by
the German manufacturer LEYBOLD-HERAEUS. This booklet
also describes 150 programs and can be found
Not too long ago I delivered a talk about the development of the
so called Mischgerät and the world's first electronic
analog computer. These devices were conceived and implemented by
Helmut Hoelzer while he was working in Peenemünde. The slides
for this talk (about 1 MB) can be found