The ternary calculating machine of Thomas Fowler
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Thomas Fowler

Balanced ternary arithmetic

Fowler's binary and ternary tables

DeMorgan's description

The reconstruction

About the machine
Carry mechanism
Instructions for use
Video demonstration

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References and links



Fowler's ternary calculating machine - the multiplier

The multiplier is entered into the machine by clipping the end of each multiplier rod onto one of three rungs of a ladder-like rotating frame, one rod for each digit of the multiplier. These rungs represent the three possible values for each digit of a balanced ternary number: if a digit of the multiplier is a “+”, the corresponding multiplier rod is clipped to the top rung of the rotating frame; likewise, for a “-” digit, the rod is clipped to the bottom rung, and a “0” digit is clipped to the central rung.

The rotating frame is mounted to an overall structure, using the central rung as the axis of rotation. The overall structure can slide laterally relative to the multiplicand and product rods, allowing the multiplier mechanism to act on each digit of the multiplicand one digit at a time.

At the opposite end of the multiplier from the rotating frame, the rods slide along a stationary cylindrical support. The rods each have a tooth that extends upwards to engage one of the product rods. As the ladder-like frame is rotated, it pushes or pulls the multiplier rods depending on the direction of rotation of the frame, and on which rung the rod is clipped.

The rotating frame has a tooth that extends to engage one the multiplicand rods. The position of the multiplicand rod is an indication of which direction the rotating frame should be turned for that digit of the multiplicand.

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