Hemmi Slide Rule Model 301A, Frequency Response For Control Engineers
Item History & Price
| Reference Number: Avaluer:4317558 | Modified Item: No |
| Country/Region of Manufacture: Japan |
The Hemmi 301 and 301A slide rules (the only difference is the 301A has a clear plastic overlay that slides underneath the cursors) exist to simplify frequency response calculations in control engineering. From the manual:
“Frequently in the field of automatic control engineering, mechanical engineering, electrical engineering, communication engineering, e.t.c., it is necessary to computer the magnitude ratios of phase shift angles for physical systems subjected to sinusoida...l inputs. This slide rule has been invented by Professor Keisuke Izawa of Tokyo Institute of Technology firstly in order to obtain the frequency responses of physical systems where the transfer functions of the systems can be broken into real linear and exponential factors.”
Whoosh! That’s the sound of slide rule instructions going right over my head.
Regarding the clear plastic overlay:
“This attachment has been invented by Professor Keisuke Izawa and Mr. Tomoaki Morinaga of Tokyo Institute of Technology especially for the computation of the frequency response of the quadratic factor.”
So, just another slide rule for everyday calculations. The Hemmi 301/301A was also sold in the USA by Post as the model 1490.
This Hemmi 301A appears almost new, with the only indication of use being some scratches on the clear plastic overlay, which are inevitable what with sliding it underneath the 4 cursors. This auction is for the slide rule, its overlay, and its cardboard case. There is no manual included. For more information about this slide rule I would refer you to Richard Hughes Smith’s article in the Fall 2001 issue of the Journal of the Oughtred Society, and the JOS Plus content associated with that article (the Hemmi manual) on the Oughtred Society web page.
This slide rule is from the collection of Robert K. (“Bob”) Otnes, PhD, one of the founding members of the Oughtred Society and the original editor of the Journal of the Oughtred Society. It is being sold by the Oughtred Society on his behalf.
The Oughtred Society was founded in 1991 by a group of slide rule collectors and is dedicated to the preservation and history of slide rules and other calculating instruments. Membership is open to anyone. Further information about the Oughtred Society can be found at: http://www.oughtred.org/.
PayPal is the only accepted form of payment. Buyers within California will be charged 7.25% sales tax.
Shipping will be by USPS Priority Mail. Shipping charges will be somewhat higher for destinations outside the USA.
“Frequently in the field of automatic control engineering, mechanical engineering, electrical engineering, communication engineering, e.t.c., it is necessary to computer the magnitude ratios of phase shift angles for physical systems subjected to sinusoida...l inputs. This slide rule has been invented by Professor Keisuke Izawa of Tokyo Institute of Technology firstly in order to obtain the frequency responses of physical systems where the transfer functions of the systems can be broken into real linear and exponential factors.”
Whoosh! That’s the sound of slide rule instructions going right over my head.
Regarding the clear plastic overlay:
“This attachment has been invented by Professor Keisuke Izawa and Mr. Tomoaki Morinaga of Tokyo Institute of Technology especially for the computation of the frequency response of the quadratic factor.”
So, just another slide rule for everyday calculations. The Hemmi 301/301A was also sold in the USA by Post as the model 1490.
This Hemmi 301A appears almost new, with the only indication of use being some scratches on the clear plastic overlay, which are inevitable what with sliding it underneath the 4 cursors. This auction is for the slide rule, its overlay, and its cardboard case. There is no manual included. For more information about this slide rule I would refer you to Richard Hughes Smith’s article in the Fall 2001 issue of the Journal of the Oughtred Society, and the JOS Plus content associated with that article (the Hemmi manual) on the Oughtred Society web page.
This slide rule is from the collection of Robert K. (“Bob”) Otnes, PhD, one of the founding members of the Oughtred Society and the original editor of the Journal of the Oughtred Society. It is being sold by the Oughtred Society on his behalf.
The Oughtred Society was founded in 1991 by a group of slide rule collectors and is dedicated to the preservation and history of slide rules and other calculating instruments. Membership is open to anyone. Further information about the Oughtred Society can be found at: http://www.oughtred.org/.
PayPal is the only accepted form of payment. Buyers within California will be charged 7.25% sales tax.
Shipping will be by USPS Priority Mail. Shipping charges will be somewhat higher for destinations outside the USA.
