lightning decibel calculator, type D
Datecirca 1935
Inventory Number1998-1-1375
ClassificationSlide Rule
Subject
Cultural Region
Place of Origin
Dimensions0.3 × 16.5 × 21.5 cm (1/8 × 6 1/2 × 8 7/16 in.)
Material
Accessoriesfour brochures for the Lightning Calculators, types A - D in library (Lib.4598a-d)
DescriptionThe Lightning Calculator for Decibels is a cardboard rectangle. There is a dark orange border around the entire rectangle and the interior is white. There are three holes through the right long edge, for placing the calculator in a binder.
There are several sets of scales: printed around the circumference of a circle on the cardboard rectangle and printed around the partial circumference of a partial concentric circle. There is a metal divot at the shared center that doubles as an axis of rotation for the superimposed cardboard circle. Some of the scales are written in black and others in red. The superimposed circle rotates to align desired scales on the circles.
The American Radio Relay's catalogue "Lightning Calculators" describes the scales on this calculator as follows:
The calculator has "a scale for each input and output level in current or voltage or power, and a transmission loss or gain scale for either voltage or power ratio plus and minus 120 or 60 db."
"USE BLACK SCALE FOR VOLTAGE OR CURRENT RATIO" is written in red letters in the bottom left-hand corner of the calculator. "USE RED SCALE FOR POWER RATIO" is written in red letters in the bottom right-hand corner of the calculator.
The back of the lightning calculator has instructions for use printed in black lettering.
There are several sets of scales: printed around the circumference of a circle on the cardboard rectangle and printed around the partial circumference of a partial concentric circle. There is a metal divot at the shared center that doubles as an axis of rotation for the superimposed cardboard circle. Some of the scales are written in black and others in red. The superimposed circle rotates to align desired scales on the circles.
The American Radio Relay's catalogue "Lightning Calculators" describes the scales on this calculator as follows:
The calculator has "a scale for each input and output level in current or voltage or power, and a transmission loss or gain scale for either voltage or power ratio plus and minus 120 or 60 db."
"USE BLACK SCALE FOR VOLTAGE OR CURRENT RATIO" is written in red letters in the bottom left-hand corner of the calculator. "USE RED SCALE FOR POWER RATIO" is written in red letters in the bottom right-hand corner of the calculator.
The back of the lightning calculator has instructions for use printed in black lettering.
Signedon front of rule: PUBLISHED BY / THE AMERICAN RADIO RELAY LEAGUE, INC / Under License by W.P. Koechel
on back of rule: Published By THE AMERICAN RADIO RELAY LEAGUE, Inc., West Hartford, Conn. / Copyrighted 1935. American Radio Relay League Inc., Printed in U.S.A.
FunctionThe Decibel Lightning Calculator is Type D in a six-type set of slide rules for making fast radio calculations. The American Radio Relay League's catalogue "Lightning Calculators" describes its function as follows:
“With [its various scales], this calculator may be used in determining decibel gain or loss in four types of problems. When input and output voltages are known, when input and output currents are known, when input and output power are known, or when input voltage to receiver and output level are known. The decibel calculator gives an instant and clear picture of what a decibel is -- its relation to power and voltage. Anyone having to do with amplifiers, transmission lines, directional antennas, etc., will appreciate this calculator. 50c POST PAID".
“With [its various scales], this calculator may be used in determining decibel gain or loss in four types of problems. When input and output voltages are known, when input and output currents are known, when input and output power are known, or when input voltage to receiver and output level are known. The decibel calculator gives an instant and clear picture of what a decibel is -- its relation to power and voltage. Anyone having to do with amplifiers, transmission lines, directional antennas, etc., will appreciate this calculator. 50c POST PAID".
Date: circa 1935
Accessories: four brochures for the Lightning Calculators, types A - D in library (Lib.4598a-d)
Object number: 1998-1-1349
Date: circa 1932
Accessories: four brochures for the Lightning Calculators, types A - D in library (Lib.4598a-d)
Object number: 1998-1-1374
Date: circa 1935
Accessories: four brochures for the Lightning Calculators, types A - D in library (Lib. 4598a - d)
Object number: 1998-1-1376
Date: circa 1935
Accessories: four brochures for the Lightning Calculators, types A - D in library (Lib.4598a-d)
Object number: 1998-1-1377
Harvard Cyclotron Laboratory
Date: 1947-2002
Object number: 2003-1-0291
Ballantine Laboratories, Inc.
Date: copyright 1953
Accessories: Instruction booklet, see 1998-1-1372b
Object number: 1998-1-1372a
Digital Equipment Corporation
Date: circa 1980
Object number: 1998-1-1042
Contina AG
Date: circa 1960
Accessories: instruction booklet; "Mathematical Handbooks" (2); copies of invoice (2); photocopy of the envelope in which David Wheatland acquired the materials (the original was destroyed in 1997)
Object number: 1990-5-0025
CASIO Computer Company, Ltd.
Date: 1970-1980
Accessories: vinyl pouch with folded over snap cover and hanging loop; batteries
Object number: 1995-1-0012
