|
1. The Classic
Series (1972 - 1982) |
 |
HP 35 (Version 1)
The first HP Calculator and the world's first calculator
with transcendental functions (SIN, COS, TAN, LN, LOG).
Introduced on February 1, 1972. So called because it had 35
keys. It was made by William Hewlett for the company's own
engineers. It had to be small enough to fit in a
shirt-pocket. Four different versions of this calculator
were manufactured over the years. This one is Version 1,
also known as Red Dot because of the whole to the right of
the ON/OFF switch, which when shifted to ON, revealed a red
dot.
Code name: N/A. Original price: $395 |
 |
HP 35 (Version 2)
This is the
second version of the HP 35. The only difference
is that the red dot was dropped as unnecessary. One could
figure out that the calculator was on, when the display was
on, so the red dot was dropped. This change happened fairly
quickly, rendering the first release of the HP 35 rather
read and highly collectable. |
 |
HP 35 (Version 3)
This is the third version of the HP 35. The only difference
is that the label on the bottom now reads "Hewlett Packard
35" instead of just "Hewlett Packard" to differentiate it
from the other calculators introduced in the mean time by
Hewlett Packard. |
 |
HP 35 (Version 4)
This is the fourth version of the HP 35. On this version,
the labels of the function keys are printed on the keys,
instead of above them, as is customary with any calculator
since then. The keys also changed size and became a bit more
elongated, as opposed to square in the previous three
versions. Square keys were an HP first - and quite the look,
in my opinion. |
HP 35 Emulator:
To operate a Java-based HP 35 (Version 4)
calculator now, please click
here! |
 |
HP 80 (Version 1)
HP's second calculator and the company's first Business
Calculator. This was the first ever calculator to introduce
a SHIFT key, hence doubling the available functions without
increasing the number of keys. Introduced on February 1,
1973. On this calculator HP changed the key xy
to yx to more properly
integrate this function in HP's RPN logic. The ENTER key was
labeled SAVE to avoid confusing business users. Code name:
N/A. Original price:$395 |
 |
HP 80 (Version 2)
As with the HP 35, when more models were introduced, the
label on the bottom of the calculator had to be changed to
identify the model number. This is version 2 of the HP 80,
showing the "80" on the label. |
 |
HP 45
HP's third calculator and second scientific, basically
improving on the HP 35. Also, the first scientific
calculator with a yellow SHIFT key. Introduced on May 1,
1973. One unique feature was the calculator's built in
timer, basically a stop watch that could be accessed by
pressing RCL then CHS, 7 and 8 all three keys at once. Code
name: Wizard. Original price: $395 |
 |
HP 65
Introduced on January 19, 1974. HP's fourth calculator, this
was the first programmable model with many new functions, a
built-in magnetic card reader, allowing users to save
programs on cards for future use. This was the most
expensive pocket calculator ever sold. It was used as a
backup computer by American astronauts during the Apollo
missions. In one of those missions in outer space, the
astronauts used the HP 65 to calculate course correction
maneuvers during the rendezvous of the US Apollo and the
Russian Soyuz spacecraft.
Code name: Superstar. Original price: $795 |
 |
HP 70
HP's second Business Calculator. HP called this one a
Financial calculator, as opposed to the HP 80, which was
sold as a Business calculator. It basically had fewer
functions than the 80. The SAVE key was now renamed back to
ENTER. Introduced on August 1, 1974 and was withdrawn a year
later. Due to its unpopularity, this is one of the rarest
ones to find.
Code name: Scrooge. Original price:$275 |
 |
HP 55
HP's sixth calculator, it was introduced on January 1, 1975
as a cheaper alternative to the HP 65. It had no card
reader, fewer steps and fewer mathematical functions.
However, it included a series of conversion functions. It
included a stopwatch function that made it rather unique
among the classics (the 45 had a timer, but it was hidden).
Code name: Merlin. Original price: $395 |
 |
HP 67
This was essentially an upgraded HP 65, but with many more
features requiring the addition of a third black shift key
(h). It was the last calculator of the Classic Series,
introduced on July 1, 1976 and on sale for 6 years .
Code name: Hawkeye. Original price: $450
 |
