Sinclair Scientific
Encyclopedia
The Sinclair Scientific calculator
was a 12-function, pocket-sized calculator, selling for about $100 in the USA and around £45 in the UK.
The Sinclair Scientific first appeared in a case derived from that of the Sinclair Cambridge
, but it was not part of the same range. At the time it was launched, in August 1975, it was a highly unusual calculator. It displays only in scientific notation - 5 digit mantissa, 2 digit exponent. Because of the way its processor (a custom chip from Texas Instruments) is designed, it relies on reverse Polish notation (RPN)
. This unusual method of mathematical problem solving meant that, for instance, to add 2 and 4, one had to enter 2, then 4, then the + symbol. There was no = key. The Scientific Programmable was an advanced version launched in 1977, again using reverse Polish notation. It could handle programs of up to 24 steps and cost £29.95. It used four AAA batteries.
The Scientific Programmable Mark 2 was powered either by a 9V battery or a mains adaptor and cost £17.22. It came with twelve sample programs, with another 294 contained in an additional four-volume library which could be bought for £4.95. Each volume was dedicated to a different application: finance and statistics, mathematics, physics and engineering, and electronics. It also used RPN
.
An ingenious aspect of the design which showed Sinclair's
inventiveness was that the machine made use of what was originally a 4-function calculator chip. Sinclair realised that by using RPN
and allowing a reduced precision of 4 or 5 significant figures displayed in scientific notation, the algorithms for scientific functions could be redesigned and compacted to fit in the same programmable space on the chip. This allowed Sinclair to adapt the relatively low-cost processor and produce an 'electronic slide rule' that fitted easily in a shirt pocket, at a price that even impecunious students could afford.
As a consequence of the compacted logical design and in common with many ground-breaking inventions, operation was a little idiosyncratic, but amazingly flexible with familiarity. Keys trebled up on functionality, important constants were printed on the case below the display, and the instruction book contained many useful keystroke sequences for common functions that were otherwise absent from the device - thus making the calculator much more versatile than the keyboard at first suggests. The log/antilog
functions used natural logs
and the trignometric functions used radians. The constants printed on the case were useful when converting between radians and degrees, and between log base 10
and log base e
.
Calculator
An electronic calculator is a small, portable, usually inexpensive electronic device used to perform the basic operations of arithmetic. Modern calculators are more portable than most computers, though most PDAs are comparable in size to handheld calculators.The first solid-state electronic...
was a 12-function, pocket-sized calculator, selling for about $100 in the USA and around £45 in the UK.
The Sinclair Scientific first appeared in a case derived from that of the Sinclair Cambridge
Sinclair Cambridge
The Sinclair Cambridge was a small pocket-sized calculator manufactured from summer 1973 by UK company Sinclair Radionics. It was available both as a kit to be assembled by the purchaser, and assembled...
, but it was not part of the same range. At the time it was launched, in August 1975, it was a highly unusual calculator. It displays only in scientific notation - 5 digit mantissa, 2 digit exponent. Because of the way its processor (a custom chip from Texas Instruments) is designed, it relies on reverse Polish notation (RPN)
Reverse Polish notation
Reverse Polish notation is a mathematical notation wherein every operator follows all of its operands, in contrast to Polish notation, which puts the operator in the prefix position. It is also known as Postfix notation and is parenthesis-free as long as operator arities are fixed...
. This unusual method of mathematical problem solving meant that, for instance, to add 2 and 4, one had to enter 2, then 4, then the + symbol. There was no = key. The Scientific Programmable was an advanced version launched in 1977, again using reverse Polish notation. It could handle programs of up to 24 steps and cost £29.95. It used four AAA batteries.
The Scientific Programmable Mark 2 was powered either by a 9V battery or a mains adaptor and cost £17.22. It came with twelve sample programs, with another 294 contained in an additional four-volume library which could be bought for £4.95. Each volume was dedicated to a different application: finance and statistics, mathematics, physics and engineering, and electronics. It also used RPN
Reverse Polish notation
Reverse Polish notation is a mathematical notation wherein every operator follows all of its operands, in contrast to Polish notation, which puts the operator in the prefix position. It is also known as Postfix notation and is parenthesis-free as long as operator arities are fixed...
.
An ingenious aspect of the design which showed Sinclair's
Clive Sinclair
Sir Clive Marles Sinclair is a British entrepreneur and inventor, most commonly known for his work in consumer electronics in the late 1970s and early 1980s....
inventiveness was that the machine made use of what was originally a 4-function calculator chip. Sinclair realised that by using RPN
Reverse Polish notation
Reverse Polish notation is a mathematical notation wherein every operator follows all of its operands, in contrast to Polish notation, which puts the operator in the prefix position. It is also known as Postfix notation and is parenthesis-free as long as operator arities are fixed...
and allowing a reduced precision of 4 or 5 significant figures displayed in scientific notation, the algorithms for scientific functions could be redesigned and compacted to fit in the same programmable space on the chip. This allowed Sinclair to adapt the relatively low-cost processor and produce an 'electronic slide rule' that fitted easily in a shirt pocket, at a price that even impecunious students could afford.
As a consequence of the compacted logical design and in common with many ground-breaking inventions, operation was a little idiosyncratic, but amazingly flexible with familiarity. Keys trebled up on functionality, important constants were printed on the case below the display, and the instruction book contained many useful keystroke sequences for common functions that were otherwise absent from the device - thus making the calculator much more versatile than the keyboard at first suggests. The log/antilog
Logarithm
The logarithm of a number is the exponent by which another fixed value, the base, has to be raised to produce that number. For example, the logarithm of 1000 to base 10 is 3, because 1000 is 10 to the power 3: More generally, if x = by, then y is the logarithm of x to base b, and is written...
functions used natural logs
Natural logarithm
The natural logarithm is the logarithm to the base e, where e is an irrational and transcendental constant approximately equal to 2.718281828...
and the trignometric functions used radians. The constants printed on the case were useful when converting between radians and degrees, and between log base 10
Common logarithm
The common logarithm is the logarithm with base 10. It is also known as the decadic logarithm, named after its base. It is indicated by log10, or sometimes Log with a capital L...
and log base e
Natural logarithm
The natural logarithm is the logarithm to the base e, where e is an irrational and transcendental constant approximately equal to 2.718281828...
.