This page shows a selection of early desktop calculators from a variety of manufacturers. Please refer to the separate brands listings for early electronic calculators from Canon, Casio, Sharp, and others.

Click on the photos for larger illustrations, or follow the links for further details.

**Friden Model 132, S/N 2811A**

Functions: ASMD, square root, 1 memory

Technology: Discrete-component, delay line memory

Display: 13 digits, 4 registers, CRT display

Dimensions: 470W x 560D x 250H, weight 19.5kg

Manufactured: Friden, USA, 1966

The Friden EC-130 from 1964 was one of the very first all-transistor electronic calculators. The circuitry was built entirely with discrete components, with internal storage provided by a mechanical delay line memory. The calculator used "reverse Polish" notation, with the four stack registers visible simultaneously on a cathode ray tube display.

The EC-132 from 1965 was basically identical to the EC-130, but with the addition of a square root function.

The machine illustrated was purchased in 1966 by the Australian Mineral Development Laboratories, at a price in the thousands of dollars. It was obsolete and sold for scrap within three years.

**Casio Model 101, S/N B-3595**

Functions: ASMD, constant, 1 memory

Technology: discrete-component DTL

Display: 10 digits, Nixie tube

Dimensions: 380W x 450D x 260H

Weight: 13.9kg

Manufactured: Casio Computer Co, Japan, 1966. (Sold by
Remington)

Casio's first electronic calculator (the Model 001) was released in September 1965, and was updated the following year to become the Model 101. Casio's first export shipment was made in September 1966, when a consignment of Model 101 calculators was sent to Australia. The machines carried a small "Remington" badge and were sold through the long-established Remington dealerships. The Casio 101 was priced at $1670, which was about 50% more expensive than a top-of-the-line fully-automatic mechanical calculator.

The Casio 101 is a very capable machine, considering the state of development at the time. The display is normally right-aligned with leading zeros, and has a backspace key to correct errors. A six-digit constant factor with a decimal point can be set on the seven front-panel dials and accessed with the K key. The leftmost dial sets the display for 0 to 9 decimal places. The single memory register can be accessed directly with the M and F keys, or it can be set for automatic accumulation of products with the Σ (sigma) key. A red = (equals) key subtracts the product, or displays the complement of the last result. The FA key left-aligns the display for division and for double-precision multiplication. The machine will multiply two 10-digit numbers to produce a 20-digit result, with the least significant digits returned in the memory register.

The
internal view shows a heavy sheet-metal card cage containing 9
logic boards, each measuring 310 x 180mm. The boards are said to
contain over 10,000 discrete components. The display board with 10
NEC Nixie-style tubes is mounted at the front of the card cage. The
keyboard frame is a heavy metal die-casting, with the power supply
mounted underneath. The moulded plastic casing (about 6mm thick)
has a removable panel in the base to give access to the hand-wired
backplane.

*Internal view (30kb)*

**Anita 1000 Series, Model 1011, S/N M2971**

Functions: ASMD, constant, percent, 1 memory

Technology: Discrete-component DTL, 7 IC chips

Display: 10 digits, Nixie tubes

Dimensions: 265W x 335D x 175H

Weight: 5.9kg

Manufactured: Bell Punch Company, England, January 1970

The Bell Punch Company of
England is generally credited with building the first production
electronic calculator - the ANITA - in 1962. This 10-key Anita
Model 1011 was made in England in early 1970, using discrete-component
diode and transistor logic and a small number of MOS integrated
circuits.
*More...*

**Casio Model AL-2000, S/N 205664**

Functions: ASMD, square root, 4 memories

Programming: 30 steps, 14 instructions, no conditionals

Technology: DTL (MSI and discrete), magnetic core memory

Display: 14 digits, miniature Nixie tube

Dimensions: 340W x 400D x 150H

Weight: 6.8kg

Manufactured: Casio, Japan, 1970. (Sold by Remington)

The AL-2000 is a very early programmable desk calculator, introduced
by the Casio Computer Co Ltd of Tokyo, Japan, in November 1969. The
machine uses a mixture of discrete-component and integrated-circuit
diode-transistor logic, and contains two special MSI (medium-scale
integration) MOS chips. A magnetic core memory module from Mitsubishi
provides 512 bits of memory (yes, *bits*) for the working
registers and the program.
*More...*

**Victor 1800 Series, Model 18-1721, S/N 4676-666**

Functions: ASMD, trig, log, powers, 1 memory

Technology: MOS-LSI (Rockwell, 6 chips)

Display: 14 digits, 7-segment neon (Panaplex)

Dimensions: 250W x 290D x 130H

Weight: 2.78kg

Manufactured: Victor Comptometer Corp, Chicago, 1973

The Victor Comptometer Corporation sold a range of attractive and functional desktop calculators under the "Victor 1800" label from around 1971.

The machine illustrated is a "scientific" model that was built in
mid-1973. It provides trig and log functions and their inverses,
powers, square roots, and reciprocals. It operates in degrees or
radians, and in common or natural logarithms. There is a single
(accumulating) memory register.
*More...*

**Imperial (Litton) Model IC-900, S/N 8D-48453**

Functions: ASMD, K

Technology: MOS-LSI, single chip (GI G-500)

Display: 8 digits, gas discharge module

Dimensions: 140W x 225D x 65H

Weight: 0.83kg

Manufactured: Made in Japan for Royal Imperial International
Frankfurt, 1973.

The Imperial IC-900 is a basic 4-function calculator that was made in Japan for Litton Industries in 1973. Litton started as a small electronics company in the 1950s, and eventually became a major supplier of military equipment. Along the way they acquired the famous "Royal" typewriter brand, which was used for a time on some mechanical and electronic calculators. Litton also owned the American Monroe brand (from 1958) and the European Triumph-Adler (from 1968).

The Imperial IC-900 uses a General Instruments G-500 processor in a 24-pin DIL ceramic pack, assisted by 28 discrete transistors. The "Panaplex"-style gas discharge display is a "Flandipak" module made by Matsushita Electric. The CPU, display, and keyboard are all dated April or May of 1973.

The calculator operates in algebraic mode, with a decimal point floating within the 8-digit range. Overflow shows the 8 most significant digits without a decimal point, but does not lock the machine. Division by zero lights all decimal points, but leaves two of the digits counting continuously until cleared. The "Constant" function is different to most later machines. After the constant (eg 2) is entered with the sequence 2 = K, it is only necesary to enter the next number and touch the function key to display the result. For example, 3 Mult shows 6, 5 Div shows 2.5, etc. Incorrect key sequences can produce large and irrelevant results.

*Internal view (31kb)*

*Circuit board detail (44kb)*

**"TE8000", S/N 55105622**

Functions: ASMD, K

Technology: MOS-LSI, single chip (TI TMS-0105)

Display: 8 digits, Futaba VFD tubes DG10R1

Dimensions: 140W x 210D x 80H

Weight: 0.76kg

Manufactured: Unknown, 1973.

Texas Instruments built the first of their single-chip MOS-LSI
calculator processors (the TMS-0100 series) in 1971. As these devices
became commercially available and prices rapidly fell, it became
possible for just about anyone to build an electronic calculator.
This TE8000 is a "no-name" four-function machine using a
TMS-0105 single-chip processor from 1973.
*More...*

Last Updated: 7 May 2011

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