twin magnetostriction oscillator
Date: circa 1926
Inventory Number: RS0205
Classification: Frequency Standard
Subject:
Maker: General Radio Company (1915-present)
Maker: (batteries) Burgess Battery Company (founded 1917)
Maker: George Washington Pierce (1872 - 1956)
Cultural Region:
Place of Origin:
Dimensions:
25 x 49 x 29 cm (9 13/16 x 19 5/16 x 11 7/16 in.)
Accessories: 3 batteries (removed during FAE inventory).
Description:
A wooden electronic box from the 1920s with a frontal control panel, metal handles on its sides, and two similar sections on top with electrical contacts.
Originally there would be two electromagnets with hollow axes placed horizontally on each of the two sections on top with the electrical contacts, through which metal bars of different lenghts could be inserted.
The front panel contains two large dials (0-100) on the center left and right, three meters with circular glass windows, two smaller knobs on the side of the dials, and several switches. An electrical cable connects together the outlets on the bottom left and bottom right of the panel.
Top can be opened to expose components and a circuit diagram that used to be affixed to the inside of the lid. Batteries.
Originally there would be two electromagnets with hollow axes placed horizontally on each of the two sections on top with the electrical contacts, through which metal bars of different lenghts could be inserted.
The front panel contains two large dials (0-100) on the center left and right, three meters with circular glass windows, two smaller knobs on the side of the dials, and several switches. An electrical cable connects together the outlets on the bottom left and bottom right of the panel.
Top can be opened to expose components and a circuit diagram that used to be affixed to the inside of the lid. Batteries.
Signedon front panel: TWIN MAGNETOSTRICTION / OSCILLATOR / TYPE 489 SERIAL No. 11 / GENERAL RADIO CO./CAMBRIDGE, MASS.
on left and right dials: WESTON ELECTRICAL INSTRUMENT CO., NEWARK, N.J., US.A. / MILLIAMPERES D.C. / WESTON / MODEL 506 TYPE F01 / PATENTS PENDING
on center dial: WESTON ELECTRICAL INSTRUMENT CO., NEWARK, N.J., US.A. / VOLTS D.C. / WESTON / MODEL 506 TYPE A04 / PATENTS PENDING
on left and right dials: WESTON ELECTRICAL INSTRUMENT CO., NEWARK, N.J., US.A. / MILLIAMPERES D.C. / WESTON / MODEL 506 TYPE F01 / PATENTS PENDING
on center dial: WESTON ELECTRICAL INSTRUMENT CO., NEWARK, N.J., US.A. / VOLTS D.C. / WESTON / MODEL 506 TYPE A04 / PATENTS PENDING
FunctionThis is a device that produces a very stable frequency output and can callibrate other oscillators, especially their magnetostrictive rods. It is composed of two identical magnetostriction oscillators put together in the same box and with their outputs connected to each other.
Its output could also be connected to a clock motor for very accurate timekeeping.
(For more information on the workings of a magnetostriction oscillator, see object RS1313).
In magnetostriction oscillators, the oscillation frequency is determined by the material and geometry of a metal rod that would go through the axis of two electromagnets on top of the box. Once the frequency of a magnetostriction rod is known, it can be used to callibrate others by having them oscillate in different oscillators and adding their outputs. One could connect this output to a loudspeaker and because of wave interference, a sound would be produced whose frequency is related to the difference in frequency of the two oscillating rods. The operator could then use a file or other means to alter the length and geometry of the rod to be callibrated, either until they both had the same frequency, or until the tone reached a particular frequency.
This device was built by General Radio on order from G.W. Pierce.
Its output could also be connected to a clock motor for very accurate timekeeping.
(For more information on the workings of a magnetostriction oscillator, see object RS1313).
In magnetostriction oscillators, the oscillation frequency is determined by the material and geometry of a metal rod that would go through the axis of two electromagnets on top of the box. Once the frequency of a magnetostriction rod is known, it can be used to callibrate others by having them oscillate in different oscillators and adding their outputs. One could connect this output to a loudspeaker and because of wave interference, a sound would be produced whose frequency is related to the difference in frequency of the two oscillating rods. The operator could then use a file or other means to alter the length and geometry of the rod to be callibrated, either until they both had the same frequency, or until the tone reached a particular frequency.
This device was built by General Radio on order from G.W. Pierce.
Primary SourcesA very similar device is described, including a picture, in George W. Pierce, "Magnetostriction Oscillators", in Proceedings of the Institute of Radio Engineers Vol 17, No.1 (January, 1929).
ProvenanceProbably from the Cruft Laboratory, Harvard University.