PSN-L Email List Message

Subject: Re: Golitsyn pendulum
From: "Ed Thelen" ethelen@........
Date: Thu, 11 Nov 1999 12:05:47 -0800


> > Sensor: Golitsyn pendulum + moving coil transducer.
....
> Could you take a picture or give a little more explanation about your
> instrument please. I don't think I've heard of it before.

It seems the original "Lehman" instrument was developed a long time ago
by Boris Golitsyn.
Quoting from
    http://psn.quake.net/sgsenstxt.html
which quotes from
    September, 1975 Scientific American Magazine
                            "The Amateur Scientist"
the following
"
When an amateur builds a seismometer, he is most likely to choose an
instrument of the
electromagnetic type developed in 1906 by Boris Borisovich Golitsyn, a
physicist who was also a
prince of the Russian Empire. A seismometer of this type picks up earthquake
waves with a
pendulum that supports a coil of insulated wire between the poles of a
magnet rigidly linked to the
earth. The relative motion between the magnet and the coil caused by tremors
in the earth
generates corresponding electric currents in the coil. The currents can be
amplified to operate a
pen recorder.
"

As best I can determine, Lehman in the late 1970's
described a particular two vertical strut instrument that he made.
Somehow his name stuck to the generic "garden gate" or
" Golitsyn" type instruments ever since.  I believe that it is
mostly PSN folks that use the term

Quoting from
      http://www.seismicnet.com/info/homefaq.txt
"CONSTRUCTION INFORMATION - INSTRUMENTS & SENSORS:
A very good article was published several years ago in the
AMATEUR SCIENTIST by Scientific American. Titled, "How To Build A Simple
Seismograph to Record Earthquake Waves at Home" by Jearl Walker.
The article was published in Scientific American, 1979, v. 241, No.1,
pg 152-161. It described the construction of a horizontal seismic sensor
and preamp circuit designed by James D. Lehman. At the time, Mr. Lehman
was with the Physics Dept., James Madision University, Harrisonburg, Va.,
22807.
"

The June 1953 issue of Scientific American,
"The Amateur Scientist", conducted by Albert G. Ingalls,
described a Golitsyn type seismometer - using a vacuum tube amplifier.
The availability of amplifiers removed the need for the large mass
and some "interesting" circuits to facilitate recording
 of the early 1900s electrical or mechanical designs.

Certainly by 1953, many commercial seismometers
were using the "garden gate" or " Golitsyn" design.

Most of these designs use a single rigid vertical strut.
I have no idea what advantage the Lehman two small
vertical strut design has other than the local hardware store
might not have large enough diameter copper tubing.

Cheers
   Ed Thelen



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Larry Cochrane <cochrane@..............>