Michael Dunn's Museum of Calculators and Other Oddities


I've been enthralled with calculators since I played with one of the first pocket ones around 1972. They strengthened an already strong interest in math and taught me my first lessons in programming (I think my first actual programming experience was on a Compucorp, card reader and all, at school). Over the years, I've built a decent little collection. Some work, some don't. Some were bought to use, some acquired as collectibles. They are arranged in rough chronological production order. Don't take any of the data here as gospel. There are some approximated entries. If you can correct anything, let me know. Click on the thumbnail to get a larger image. Costs are in Canadian dollars. The "Forensic #" is a quick test to gauge the accuracy of the trig algorithms, the number of internal digits, and sometimes even the chip (set). The ideal result is 9. Check the site for more info (a couple of my results for non-working units were taken from this site). The "69!" entry (get your mind out of the gutter) gives the time to calculate the factorial of 69. Last updated July 29, 2004.

Click here to see a calculator book published in the UK in 1976 and republished by Coles Bookstore (Canada) in 1980.

Click here to see a TI calculator book from 1978.





Manufacturer
Wang Labs
Model
LOCI-2 (2A)
Mfg. Date
1967 (s/n 3059)
Accession Date
~1982
Orig. Cost
~$3000
Batteries
Made in
USA
Display
Nixie tubes
Programming
80 steps (1 per keystroke), punched card
Digits (guards)
10
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
16, continuous (magnetic core)
Conversions
Comments
A breakthrough calculator, this has a log-antilog-computing circuit at its heart. Therefore, multiplication and division are done internally as log-add-antilog! Of course, this enables the relatively simple inclusion of functions like square and square-root in addition to log and antilog. Circuitry is entirely discrete transistor (over 1,200); not a single IC. There is no program memory per se. Instead, the card reader has a contact for every possible hole position, and the card itself becomes a ROM! Very cool. Here are the manuals.


Manufacturer
Rapid Data Systems & Equipment Ltd.
Model
Rapidman 800
Mfg. Date
1972 (s/n 122762)
Accession Date
Apr 2004
Orig. Cost
$100? ($400!?)
Batteries
9V
Made in
Canada
Display
LED
Programming
Digits (guards)
6.2/8.2
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
One of the earliest readily available machines, I think this might be the first calc I ever had a chance to sit and play with. Odd olive/khaki colour, I think it also came in black. It's a bit of a chore to use. You have to clear it before doing a +/- calculation or else the previous result will get used in an RPN-ish manner. In fact, doing addition and subtraction is just like RPN, which is also how many mechanical adding machines worked I guess. See the instructions on the back. The keys have a cool feel, with the numbers being recessed about 1mm. The display is fixed at two decimal places, but, you can use numbers >999999.99 (only millionaires would need to use such numbers, and there were fewer of them in 1972). When you exceed the display's capacity, the indicator to the right of the display comes on, indicating 1 or 2 undisplayed MSDs. When you're finished, divide by 100 to see the integer part. Overflow beyond 8.2 and you see
 0 0 0.0.0.0.0.0. 


Manufacturer
Royal (Litton)
Model
Digital V
Mfg. Date
1972-1973
Accession Date
Orig. Cost
Batteries
Internal NiCds
Made in
Japan
Display
Green VFD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments


Manufacturer
Victor Comptometer Corp.
Model
MEC/1
Mfg. Date
1973
Accession Date
~2000
Orig. Cost
$280
Batteries
6 AA(?) internal NiCds
Made in
USA
Display
Burroughs Panaplex II planar neon
Programming
Digits (guards)
12
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
You've gotta love those Panaplex displays... Also has an AC power cradle (not shown).


Manufacturer
Simpson-Sears
Model
Digimatic 41007
Mfg. Date
~1973
Accession Date
Mar 2004
Orig. Cost
Batteries
3 AA
Made in
Hong Kong
Display
LED
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
Labelled/built for Simpson-Sears (Canada), this calc found its way to Australia and back again. The batteries don't really fit well. Have AAs gotten longer in the last 30 years?


Manufacturer
Sharp
Model
Elsi Mate EL-120
Mfg. Date
1973
Accession Date
Mar 2004
Orig. Cost
Batteries
3 AA
Made in
Japan
Display
Green VFD
Programming
Digits (guards)
9.3 (3 physical)
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
The weirdest calc I've ever known. The button on the side increments the display by 1, like a person counter clicky thing. On top of that, the display is only 3 digits! If the number is longer than this, the display flashes between groups of digits, either automatically or manually. Up to 4 groups might be displayed - 3 to the left of the decimal, 1 to the right. "Comma" graphics indicate which group is showing. Click here to see an animation of the display in auto mode. The build quality is quite rugged, and there's a cm scale molded into the back. Maybe this was meant for shop use??? Inventory taking??


Manufacturer
Melcor
Model
400
Mfg. Date
1973-1974
Accession Date
1974
Orig. Cost
~$80
Batteries
9V
Made in
USA
Display
LED
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1
Conversions
Comments
My main calculator for a while. I quite liked its look and feel.


Manufacturer
Novus
Model
650
Mfg. Date
1975
Accession Date
~1975
Orig. Cost
$20
Batteries
9V
Made in
USA
Display
LED
Programming
Digits (guards)
6
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
At one point, I had modified this to be a stopwatch (the picture), actually using the calculator circuit (probably why I bought it). I later dismantled and gutted it, and built a binary counter do-nothing-box into it with four LEDs where the display used to be. I don't recall why.


Manufacturer
Microlith
Model
Scientific 205
Mfg. Date
1974-1976
Accession Date
1974-1976
Orig. Cost
Batteries
9V
Made in
Hong Kong
Display
Blue VFD
Programming
Digits (guards)
8+2 (0)
Forensic #
6.58003
69!
5s
Fractions
Stats
Non-decimal
Memory
1
Conversions
deg/rad
Comments
Trigs and logs computed to 6 digits. Interesting exchange key <-> exchanges display with last-entered number.


Manufacturer
Novus (National Semi)
Model
Mathematician 4510
Mfg. Date
1975
Accession Date
Orig. Cost
Batteries
9V
Made in
Malaysia
Display
LED
Programming
Digits (guards)
8 (0)
Forensic #
8.843762
69!
Fractions
Stats
Non-decimal
Memory
1
Conversions
Comments
A very interesting calc. A rare non-HP RPN machine! Amazingly for a scientific, NO exponent! Trig and some other functions only computed to 7 digits. Even integer exponentiation is inaccurate (e.g., 2^16=65535.82!). Power saver switches display to all decimal points after about 25 seconds. Has a key to sum square of display into memory.


Manufacturer
Texas Instruments
Model
SR-56
Mfg. Date
1976
Accession Date
Jan 1977
Orig. Cost
$200
Batteries
3 AA NiCd in cartridge
Made in
USA
Display
LED
Programming
100 steps (1 per keystroke), volatile
Digits (guards)
10+2 (2-3)
Forensic #
9.000004661314
69!
n/a
Fractions
Stats
basic
Non-decimal
Memory
10, volatile
Conversions
Comments
A classic!!! I got lots of early programming experience on this. A great feeling calc. Best thing TI ever did! Can be mated to the PC-100 thermal printer. Interesting - a slide switch for degree/grad selection, but a key command to switch to radians. Click here to see a program sheet for my SR-56 pièce de résistance, a Tug-of-War game. Here's the back. And check out the nice manuals.


Manufacturer
Texas Instruments
Model
TI-30
Mfg. Date
~1977
Accession Date
June 2004
Orig. Cost
~$25
Batteries
9V
Made in
USA
Display
LED
Programming
Digits (guards)
8/5+2 (2-3)
Forensic #
9.177087103
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
A very popular calc in its day. Power saver displays a "walking" decimal point. During long computations (e.g., trig), the RH digit goes through all sorts of neat contortions to show it's thinking. EE key can shift decimal around in either direction in steps of one power of ten. The cute little tick marks in the upper-left are the DRG indicator (none for deg, 1 for rad, 2 for grad). Combine with a negative sign in the left-most position, and you get a strange looking display! Integer exponentiation is inaccurate (2^16=65536.000534).


Manufacturer
Commodore
Model
PR100
Mfg. Date
1978
Accession Date
Orig. Cost
$70
Batteries
3 AA NiCd fixed
Made in
England
Display
LED
Programming
72 steps (1 per keystroke)
Digits (guards)
8+2 (2)
Forensic #
9.14705679 (12sec)
69!
1.5s
Fractions
Stats
1-var, P&C, LR
Non-decimal
Memory
10
Conversions
deg/rad, R/P, H/HMS, metric (4), cartesian/spherical!
Comments
Cute display has exponent digits smaller than mantissa. A surprisingly sophisticated machine for the time and price. Here's a friend's working unit. And with manuals.


Manufacturer
Texas Instruments
Model
TI-58C
Mfg. Date
1980
Accession Date
2000
Orig. Cost
Batteries
3 AA NiCd in cartridge
Made in
USA
Display
LED
Programming
y
Digits (guards)
10/8+2 (3)
Forensic #
9.000004661314
69!
Fractions
Stats
1-var
Non-decimal
Memory
10, continuous
Conversions
R/P, H/HMS
Comments
This is the continuous-memory version of the original TI-58. The card seen under the display is not magnetic, but simply labels the definable buttons. You can make them for your own programs, or slip in one that comes with a ROM software module. The module I have includes 25 cards! The calc is shown mounted on the PC-100C thermal printer (acc. 2003). Looking at the guts, I noticed that two chips (probably memory) are stacked on top of each other. IBM also once used this trick in a PC (AT?). Pgming model includes flags.


Manufacturer
Nixdorf
Model
LK-3000
Mfg. Date
1980 (cartridge 1979)
Accession Date
2000
Orig. Cost
$170
Batteries
4 AA NiCd fixed
Made in
Malaysia
Display
16 chr. alphanumeric LED (14-segment)
Programming
Digits (guards)
7 or 8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1
Conversions
Language!, metric, currency
Comments
A language translator with calculator functionality. I have the English/Polish module. To do calculations, you actually need a separate calculator module. There wasn't enough ROM space to combine calc and language! Modules were also available with PDA or database functionality as well as one containing 1980 Olympics results! Bet that one sold well. Oddly, the module itself contains not only the ROM, but the processor too (a Mostek 3870 microcontroller (Fairchild F8 core)). The display is comprised of four "intelligent" alphanumeric modules. Although I got the unit fixed up enough to power up, the keyboard connector is broken, so for now, I don't know any more about its functionality. Display goes into power-saving mode after ~20s. A 2s exposure is shown in the picture. Here's the unit saying something else. There's a bad display connection too, as the words and power-save display aren't quite "right".


Manufacturer
Hewlett-Packard
Model
HP-85
Mfg. Date
1980
Accession Date
Apr 2004
Orig. Cost
~$4000
Batteries
Made in
USA
Display
CRT, 32x16 character, 256x192 graphics
Programming
BASIC, 14K RAM
Digits (guards)
12+3 (0)
Forensic #
8.99999864267 (0.3sec)
69!
0.5s, as a program!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
More a computer than a calc, it's here because it's H-P, and because it can be used as a calc, simply by entering expressions directly. Also, the processor architecture and speed lean towards calculator-type designs. Although the processor clock is only 613kHz, the architecture is streamlined for math and is a bit RISC-like. For example, the operation r1=r1+r2 takes one clock (well, four phases of one clock, so you might say the clock is actually 2.452MHz). There are 64 registers. It appears to run significantly faster than a contemporary 8080 or Z80 system. 64-line history. Amazingly high integration for 1980, the entire machine consists of 11 LSI chips that do everything - processor, ROMs, keyboard, I/O, video, tape drive, printer. There is essentially NO digital support circuitry. Most of the remaining circuitry is for power and the CRT. Eight 16Kb DRAMs, plus four more for video memory. Dynamic range of 10^+/-499. This example has two plug-in modules, each providing an HP-IB (GPIB) interface. An HP page about it. And another.


Manufacturer
Hewlett-Packard
Model
HP-15C
Mfg. Date
1984
Accession Date
Sept 1984
Orig. Cost
$165
Batteries
3 LR44
Made in
USA
Display
LCD
Programming
about 300 steps with 21 memregs
Digits (guards)
10/7+2 (0)
Forensic #
9.000417403 (5sec)
69!
0.75s
Fractions
Stats
1-var, P&C, LR
Non-decimal
Memory
67 max (no pgm mem)
Conversions
deg/rad, R/P, H/HMS
Comments
One of the best calculators ever made -- by anyone. Shows well even on its 20th birthday (amazingly, the 15's sister calc, the HP-12C Financial, is still being made after over 20 years! Quality never goes out of fashion). RPN of course. Program/register memory trade-off completely under user control. The "C" in HP-15C really means continuous. Even the display is held when powered down. Oddest attribute: No normal floating decimal! Easy enough to get used to, and it's always possible to view the full 10-digit mantissa with a keystroke. Automatic 1000s separators (commas) can be changed to decimal points (decimal becomes comma). I tend to keep it in sci/eng mode with a comma decimal... Original batteries lasted for >12 years. Nuclear? Claims to fame: Complex numbers and matrices. Full implementations - all relevant functions work in complex mode, matrices can be complex. Computes integrals, roots. Does non-integer factorials! Takes a bit over 2 seconds regardless of the argument. Flags and full range of comparisons in program mode - more than visible on the front panel. I-register allows indirection with branching, register and flag addressing, and other functions. Painless program editing - memory automatically shifts to make room or close gaps. Click here to see a couple of simple programs. Nice manuals. There's even a site dedicated to the 15 and to bringing it back into production!


Manufacturer
Sharp
Model
Elsi Mate EL-407
Mfg. Date
~1985
Accession Date
~2001
Orig. Cost
Batteries
2 1.5V button
Made in
Japan
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1 (continuous)
Conversions
Comments
An alarm clock plus very basic calculator.


Manufacturer
Casio
Model
fx-451
Mfg. Date
1985
Accession Date
Feb 1986
Orig. Cost
$36
Batteries
none
Made in
Japan
Display
LCD
Programming
Digits (guards)
10+2 (1)
Forensic #
9.0000157179
69!
1.25s-1.75s depending on light
Fractions
yes, can store in mem and do 4-func math
Stats
1-var
Non-decimal
base 2/8/16, logic ops
Memory
1
Conversions
R/P, H/HMS, metric (8)
Comments
Fully solar - no battery. I also owned the predecessor to this, the fx-450. When the 451 came out, feature-itis compelled me to buy it - it had added metric conversions and four more constants! I sold my 450. In some ways though, I preferred the 450. It felt a bit more solid - the fold-out keyboard was significantly thicker and stronger. Oh well, both nice machines. One of, if not the first to include built-in physical constants (13 (9 on the 450)). The first I'm pretty sure to combine solar, constants, fractions, and logical ops (and metric conversions) in one machine, and virtually unrivalled to this day! (well, maybe not) The Engineering mode keys are neat. Using them, you can bounce the decimal around in jumps of 3, either way, in case you prefer microfarads to nanofarads for instance. A rare instance of inverse trig functions being available in a single keystroke. Apparently, the museum's example is a rarer version with a larger solar cell.


Manufacturer
Majestron
Model
watch
Mfg. Date
Accession Date
Jan 2002
Orig. Cost
Batteries
Made in
Hong Kong
Display
LCD
Programming
Digits (guards)
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments


Manufacturer
?
Model
DC-2
Mfg. Date
Accession Date
Apr 2004
Orig. Cost
Batteries
2 L1130 1.5V
Made in
Taiwan
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
Sqrt! Reminiscent of the Commodore PET, no?


Manufacturer
Model
Compucard
Mfg. Date
Accession Date
Orig. Cost
Batteries
2 G10 1.5V
Made in
Taiwan
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments


Manufacturer
Toshiba
Model
LC-851
Mfg. Date
1988
Accession Date
Jan 2002
Orig. Cost
Batteries
1 3V "LF-1/3W" (very close to a 2325, but even a 2025 works)
Made in
Japan
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
Noticeably slower than a modern 3V calc. Sq, sqrt.


Manufacturer
Model
Mutual Group promo
Mfg. Date
Accession Date
Apr. 2004
Orig. Cost
Batteries
Solar
Made in
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
Sqrt.


Manufacturer
Model
matchbook
Mfg. Date
Accession Date
~1996
Orig. Cost
Batteries
1 L1131 1.5V
Made in
China
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
A great little novelty calc, I got this for free by pretending to be a smoker and filling out a questionnaire.


Manufacturer
Aurex
Model
SC-101
Mfg. Date
~1995
Accession Date
May 2004
Orig. Cost
Batteries
2 AG13 1.5V
Made in
China?
Display
LCD
Programming
Digits (guards)
10/8+2 (2)
Forensic #
8.99999863704
69!
0.25s
Fractions
Stats
1-var
Non-decimal
base 2/8/16, arithmetic only
Memory
1, continuous
Conversions
D/R/G, R/P, H/HMS
Comments
This calc has the same part number and functionality as one below, but is in a totally different case. Same story as the SC-107, but at least they changed the number for that one. Most notes for either below apply to this as well. Generic instruction booklet - no company name.


Manufacturer
Steven Costenoble
Model
SciCalcRPN 2.0
Mfg. Date
1996
Accession Date
2000
Orig. Cost
Batteries
Made in
USA
Display
Programming
Digits (guards)
14+3 (3)
Forensic #
8.9999999998325678
69!
~0s
Fractions
Stats
1-var, P&C
Non-decimal
base 2/8/16, logical, shifts, mod, selectable word size...
Memory
10, continuous
Conversions
deg/rad
Comments
Virtual RPN calc. User-selectable display font. Dynamic range of about 10^+/-300.


Manufacturer
Model
CAL101
Mfg. Date
Accession Date
2001
Orig. Cost
Batteries
1 G10 1.5V
Made in
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
Not made by National, but given away by them promotionally. No OFF button, it just times out. Surprising for this class of unit, a sqrt key. Cool viscous-damped display cover flips open to act as a stand.


Manufacturer
Casio
Model
Data Bank DC-2000/130
Mfg. Date
1997
Accession Date
~2000
Orig. Cost
~$8
Batteries
1 2032 3V
Made in
China
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, continuous
Conversions
Comments
A cheap little pocket organizer. Memory is actually capacitor-backed while battery is changed. FYI, power consumption is 240µW...


Manufacturer
John Brochu
Model
CalcWorks 1.5.4
Mfg. Date
1999
Accession Date
1999
Orig. Cost
Batteries
Made in
USA
Display
Programming
Digits (guards)
12+2 (8)
Forensic #
Reads 9, actually 8.999999999999992
69!
~0s
Fractions
Stats
Non-decimal
base 2/8/10/16, logical, shifts, selectable word size...
Memory
10, volatile
Conversions
DRG, P/R, H/HMS(frames), ft/ft-inch, many metric
Comments
Virtual calc. Switchable between RPN, simple, and algebraic. Allows all the logical ops in base 10! Has 16 physical constants - editable in case you move to a different universe (conversions also editable). Virtual "paper tape" can be saved and recalled.


Manufacturer
Casio
Model
CFX-9850GB plus
Mfg. Date
~1999
Accession Date
Mar 2000
Orig. Cost
~$90
Batteries
4 AA, 1 2032 backup
Made in
Malaysia
Display
3-colour (variable pixel) graphic LCD, 128x64
Programming
BASIC-like language, 28KB
Digits (guards)
10+2 (5)
Forensic #
9.00000000733343 (0.3sec)
69!
0.25s
Fractions
yes, can store in mem, do 4-func math, 1/x, x2
Stats
1-var, P&C, LR, etc, etc
Non-decimal
base 2/8/16, logic ops, mixed-base calcs
Memory
28, continuous, plus many other data-types stored
Conversions
D/R/G, R/P, H/HMS
Comments
Is it a calculator or a computer? Yes. Computer power at calculator speed unfortunately. Very thorough set of statistical and analysis functions, including many types of graphs. Fairly good implementations of complex numbers and matrices. Editable history of course. Numerical differentiation, integration, summation. Can connect to printer, computer, or other calc. Can solve sets of equations with up to six unknowns. Find roots of 2nd & 3rd-order eqns, including complex ones. Graphing, including interactive eqn solving, multiple overlaid or separate graphs, zooming, constructing a table of values or graph a table, drawing multiple graphs and "animating" between them, statistical/probability graphs... Spreadsheet-like operations. Curve fitting (lin to 4th-order, exp, periodic...). Financial funcs. The picture shows 3 graphs and the intersection point of 2 of them. I've enhanced the LCD display in the picture, as it's pretty poor in real life.


Manufacturer
Hewlett-Packard
Model
HP-6S (Solar)
Mfg. Date
~2000
Accession Date
Mar 2001
Orig. Cost
$10 ($15 solar)
Batteries
2 LR43 (1 solar)
Made in
China
Display
LCD
Programming
Digits (guards)
10+2 (2)
Forensic #
8.99999863704
69!
0.25s (non-solar), 1.5s (solar)
Fractions
yes, can store in mem and do 4-func math
Stats
1-var
Non-decimal
base 2/8/16, logic ops
Memory
1
Conversions
D/R/G, R/P, H/HMS
Comments
Funny -- the two versions of this calc are both called 6S. You'd think that moniker would be reserved for the solar. This model is actually made by Chinese company Karce. I don't know if H-P had a hand in the design, or if they have simply taken it as-is and rebranded it. I guess it's their way of establishing a presence in the scientific bottom-end. Not RPN! Note that the Aurex SC-108 is also a Karce rebrand and identical in function to the H-P! The odd thing about the solar - there's no power switch! It's always on. I try to keep it well-illuminated, leaving the top of the calc sticking out of its pouch, so as to maximize battery life. The AC button kinda behaves like a power switch, doing a full reset. Continuous memory, as long as you don't hit that button! Yet, the non-solar is continuous for memory and modes. Interesting that the 2-cell non-solar is significantly faster than the 1-cell solar, though the solar does speed up in bright light. Really! Small exponent digits on solar only. The non-solar is a bit thicker and more sturdy than the solar! Its blue colour sure makes it hard to read the legends. It's also better shielded. The solar has an internal LED! I can only guess this acts as an OVP in case the 4-section solar battery puts out too much juice!


Manufacturer
Hewlett-Packard
Model
HP-30S
Mfg. Date
~2000
Accession Date
Mar 2001
Orig. Cost
~$25
Batteries
2 LR44 1.5V
Made in
China
Display
LCD 2-line, upper is 11chr 5x7 dot-matrix
Programming
1 expression with up to 4 variables can be stored
Digits (guards)
10+2 (spec is 24 digits internal)
Forensic #
9, exactly! (2sec)
69!
0.5s
Fractions
yes, can store in mem, do 4-func math, x2
Stats
1-var, P&C, LR
Non-decimal
nope!
Memory
11, continuous
Conversions
D/R/G, R/P, H/HMS, frac/dec, metric (62 incl. trivial ones like m/km and less trivial like ft/mi)
Comments
Since the HP-30 laughed at the forensics test, I tried a tougher one, using 1 instead of 9: foren(1)=1.0000000005536418873860643... Seems I can get an infinite number of digits, which reinforces the theory that binary is being used instead of BCD, and I'm just drawing out conversion error. See TI below for a very similar unit. Comes with 3 different-coloured faceplates for your aesthetic enjoyment. Display has "slashes" between digits for fraction display, and thousands-separator commas above the digits. Decimal-to-fraction conversion is cool! Whoa!!! Just discovered buggy fraction behaviour: Enter 71/333 as a fraction, divide by 10, you get 10/475! Not only wrong, but unreduced!!! It's the Pentium flaw all over again. It seems though that current production has fixed this (I tried one in a store). HP support has been friendly, but has yet to supply a replacement. The museum has notified the technical press! Menu of 12 physical constants. Conversions include Imperial gallon. Finds roots of quadratic eqns. Solves (finds intersection) for pairs of linear eqns! Docs are not like the good old days. Instead of a nice book, we get two large sheets of paper, one with an operating summary, one with examples. So, just what kind of calculator is this? It's not RPN. It's not normal algebraic entry. It's a member of what seems to be an increasingly common type of machine, where you basically enter an expression as you'd write it. This is okay or even nice sometimes. They do tend to have history stacks, so you can go back and redo/edit a previous expression. But, I believe most serious users do not think in this outside-in way. It's the polar opposite of RPN after all. It also means that monadic operators (e.g., 1/x, x2) take two keystrokes, as you must press = after the operator. In fact, many operators (e.g., sqrt, trig, log) take four keystrokes to work on the display register (op, 2nd, Ans, =). Yuck.


Manufacturer
Texas Instruments
Model
TI-30X IIB
Mfg. Date
2001
Accession Date
~2002
Orig. Cost
$20-$30
Batteries
1 2025 3V
Made in
China
Display
LCD 2-line, upper is 11chr 5x7 dot-matrix
Programming
Digits (guards)
10+2 (3)
Forensic #
9.000003512065 (2.5sec)
69!
0.4s
Fractions
yes, can store in mem, do 4-func math, 1/x, x2, even arbitrary root extraction for simple cases!
Stats
1-var, P&C, LR
Non-decimal
nope!
Memory
5, continuous
Conversions
D/R/G, R/P, H/HMS, frac/dec
Comments
Very hard to replace battery: Remove four tiny screws, then carefully unsnap case halves. Guess they just want you to buy a new one. Has internal LED!!! Probably OVP for solar version - they forgot to leave it out... Many similarities to the HP-30 above (including the number! See the HP's closing comments as they apply to the TI too) lead one to believe they might have been designed and manufactured by the same Chinese company. What a scary thought. Display has "slashes" between digits for fraction display. Decimal-to-fraction conversion is cool! Docs are not like the good old days. Instead of a nice book, we get a few sheets of paper with an operating summary and examples. Here's a really good (bad) example of what I was talking about for the HP30: To take the square root of the current display takes five keystrokes!!! 2nd, sqrt, 2nd, Ans, = ! Double yuck. So, is this the spiritual descendant of the original TI-30? Or did they just run out of numbers...


Manufacturer
?
Model
"iMac" calculator
Mfg. Date
2001-2002
Accession Date
2002
Orig. Cost
Batteries
1 2032 3V (3 AAs for radio)
Made in
Display
LCD
Programming
Digits (guards)
12
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, continuous
Conversions
Comments
Calc, clock/alarm/calendar, thermometer, and FM radio!


Manufacturer
?
Model
Keychain calculator
Mfg. Date
2001-2002
Accession Date
2002
Orig. Cost
Batteries
1 LR621
Made in
Display
Programming
Digits (guards)
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
Conversions
Comments
Sqrt!


Manufacturer
Aurex
Model
SC-107
Mfg. Date
~2001
Accession Date
~2001
Orig. Cost
<$10
Batteries
2 L1131 1.5V
Made in
China
Display
LCD
Programming
Digits (guards)
10/8+2 (2)
Forensic #
8.99999863704
69!
0.25s
Fractions
Stats
1-var
Non-decimal
base 2/8/16, arithmetic only
Memory
1, continuous
Conversions
D/R/G, R/P, H/HMS
Comments
Made by Karce. Battery compartment is actually accessible under a removable cover, but batteries are virtually impossible to remove. Still requires case disassembly, or maybe very deft work with a pointy X-Acto! Looks like the case and the battery cover were designed by different people: The case works better with thicker LR44s (they're removable), whereas the cover will only allow the thinner L1131s! Has table of physical constants stuck inside case! Same calc as SC-101 below. Has odd function (above left parenth) that exchanges display with some "internal register" - seems to hold the last result or second-last entered number. Angular mode and mem continuous, but not operating mode! Backspace key. Complex number mode! Works for basic arithmetic only though. Generic instruction booklet - no company name.


Manufacturer
Aurex
Model
SC-108
Mfg. Date
~2002
Accession Date
~2002
Orig. Cost
<$10
Batteries
1 G10 1.5V
Made in
China
Display
LCD
Programming
Digits (guards)
10+2 (2)
Forensic #
8.99999863704
69!
1s
Fractions
yes, can store in mem and do 4-func math
Stats
1-var
Non-decimal
base 2/8/16, logic ops
Memory
1, continuous
Conversions
D/R/G, R/P, H/HMS
Comments
Presumably made by Karce; identical key functions to the HP-6S! PCB is amenable to solar connections. As with the non-solar 6, all mode settings are held when off. Manual hilariously claims "158 Functions"! Generic instruction booklet - no company name.


Manufacturer
Aurex
Model
SC-101
Mfg. Date
~2003
Accession Date
2003
Orig. Cost
<$10
Batteries
2 LR44 1.5V
Made in
China
Display
LCD
Programming
Digits (guards)
10/8+2 (2)
Forensic #
8.99999863704
69!
0.3s
Fractions
Stats
1-var
Non-decimal
base 2/8/16, arithmetic only
Memory
1, continuous
Conversions
D/R/G, R/P, H/HMS
Comments
Karce? No expense spared: Six screws holding case together. Same calc as SC-107. Has odd function (above left parenth) that exchanges display with some "internal register" - seems to hold the last result or second-last entered number. Angular mode and mem continuous, but not operating mode! Backspace key. Complex number mode! Works for basic arithmetic only though. Manual hilariously claims "128 Functions"! Generic instruction booklet - no company name. Same model number and functions as previous SC-101, just a different case!


Manufacturer
Sharp
Model
EL-546V (or VB)
Mfg. Date
2003-4
Accession Date
Apr. 2004
Orig. Cost
$25
Batteries
2 LR44/A76 1.5V & Solar
Made in
China
Display
LCD 2-line, upper is 12chr 5x5 dot-matrix
Programming
1 expression (not storable) with up to 7 variables can be entered and repeatedly evaluated
Digits (guards)
10+2 (2)
Forensic #
8.99998762105 (0.8sec)
69!
0.1s or less
Fractions
yes, can store in mem and do 4-func math
Stats
1-var, P&C, LR & 5 non-linear types
Non-decimal
base 2/8/16, logic ops
Memory
7, continuous
Conversions
D/R/G, R/P, H/HMS, frac/dec, Metric (22)
Comments
"327 Functions"! Table of physical constants (40) and metric conversions in cover to look up the 2-digit code used to access that function or number. Has Imperial gallon and ounce conversions, not just damn US ones! See applicable HP-30S notes re equation-entry type calcs. However, operation for monadic prefix operators (like sqrt) on the current result is improved: one only needs to press (e.g.) sqrt, then equals. The Ans key is implied and automatically inserted. Hyperbolics and R/P conversions on the "math" menu key. Has an annoying attribute: When entering an expression, operators are displayed on the upper line, but numbers enter onto the lower line. When a number entry is done, it gets "pasted" into the upper line. The history stack is volatile, which is a real pain when combined with the auto-off "feature"! Can solve sets of equations with up to three unknowns. Complex numbers can be entered normally or in polar form - basic math, 1/x, x2 only. Numerical integration and differentiation.


Manufacturer
Casio
Model
fx-991MS
Mfg. Date
2003
Accession Date
Apr. 2004
Orig. Cost
$23
Batteries
1 LR44 1.5V & Solar
Made in
China
Display
LCD 2-line, upper is 12chr 5x6 dot-matrix
Programming
1 expression (not storable) with up to 8 variables can be entered and repeatedly evaluated, or, one can repeatedly execute statements in the history stack (also not stored).
Digits (guards)
10+2 (2)
Forensic #
8.99999863704 (1sec)
69!
0.25s
Fractions
yes, can store in mem, do 4-func math, 1/x, x2, x3, fractions in both parts of an exponent!, even arbitrary root extraction for simple cases!
Stats
1-var, P&C, LR & 5 non-linear types, probability distributions
Non-decimal
base 2/8/10/16, logic ops, mixed-base calcs
Memory
9, continuous
Conversions
D/R/G, R/P, H/HMS, frac/dec, Metric (20)
Comments
Table of physical constants (40) and metric conversions in cover to look up the 2-digit code used to access that function or number. Has Imperial gallon (but not ounce) conversion, not just damn US one! Case even tougher to open than TI-30! See applicable HP-30S notes re equation-entry type calcs. However, operation for monadic prefix operators (like sqrt) on the current result is improved: one only needs to press (e.g.) sqrt, then equals. The Ans key is implied and automatically inserted. Switchable comma/period separators like the HP-15! The history stack is volatile, which is a real pain when combined with the auto-off "feature"! Can enter and display numbers using metric prefixes, from femto to Tera!!! Engineering mode keys bounce the decimal around just like the fx-451. Finds real & complex roots up to third-order. Solves eqns for any variable. Can solve sets of equations with up to three unknowns. Complex numbers can be entered normally or in polar form - basic math, 1/x, x2, x3 only. Numerical integration and differentiation. Good range of matrix (& vector) operations (up to 3x3). Finally, an equation-type calc that puts "Ans" on a direct key instead of a "shifted" one! What are the other mfrs thinking?!?


Manufacturer
Aurex
Model
SC-6103
Mfg. Date
~2003
Accession Date
June 2004
Orig. Cost
$15
Batteries
1 2025 3V
Made in
China
Display
LCD 2-line, upper is 12chr 5x7 dot-matrix
Programming
1 line with up to 9 variables can be stored
Digits (guards)
10+2 (3)
Forensic #
9.000002051244 (1.4sec)
69!
0.75s
Fractions
yes, can store in mem, do 4-func math, 1/x, x2, x3
Stats
1-var, P&C, LR & 5 non-linear types
Non-decimal
base 2/8/10/16, logic ops, mixed-base calcs
Memory
9, continuous
Conversions
D/R/G, R/P, H/HMS, frac/dec
Comments
Made by ?. Surprisingly, has a 32kHz watch crystal inside, yet no time functions. Remarkably similar to Casio fx-100MS, and also pretty close to 991 above, yet the forensic result does not match any other calc in the forensic master-list. See applicable HP-30S notes re equation-entry type calcs. However, operation for monadic prefix operators (like sqrt) on the current result is improved: one only needs to press (e.g.) sqrt, then equals. The Ans key is implied and automatically inserted. The unit can maintain an enormous history stack; I stopped counting at 100! Instructions say 750 characters. And, it is non-volatile! Engineering mode keys bounce the decimal around like the fx-451. Almost programmable!: Multiple expressions can be entered on one line, with the calc stopping to display each result, or simply continuing to the next expression. This line can also be stored in a dedicated memory. Surprisingly good instruction "sheet" even has "Aurex" name on it! Decimal to fraction only works on non-repeating decimals unless... the display is the result of a calculation. E.g., the result of 1/3 will convert to a fraction, but type in .333333... and you're out of luck! Finds real & complex roots up to third-order. Can solve sets of equations with up to three unknowns. Complex numbers - basic math, 1/x, x2, x3, sqrt only. Not bad! Numerical integration. Another equation-type calc that puts "Ans" on a direct key instead of a "shifted" one! Congratulations. So, isn't this interesting: A cheap generic calc that is in many ways superior to the Casio and Sharp above. Hell, it's interesting that such a sophisticated machine is even available as a generic!


Manufacturer
Busrel (yeah, right)
Model
"BRB-2001"
Mfg. Date
~2003
Accession Date
June 2004
Orig. Cost
Batteries
2 L1130 1.5V
Made in
China?
Display
LCD
Programming
Digits (guards)
8
Forensic #
69!
Fractions
Stats
Non-decimal
Memory
1, volatile
Conversions
Comments
Faux cell-phone. Sqrt. Key beep.


Manufacturer
"Merangue"
Model
SC516BL
Mfg. Date
~2004
Accession Date
July 2004
Orig. Cost
$8
Batteries
1 2025 3V
Made in
China
Display
LCD 2-line, upper is 12chr 5x7 dot-matrix
Programming
Multiple user formulas can be stored (up to ~170 chrs total, non-volatile); 38 pre-programmed formulas.
Digits (guards)
10+2 (14!)
Forensic #
9 (exactly!) (2.4sec)
69!
0.4s
Fractions
Can do 4-func math, but that's it. Uses a dedicated mode, memories unavailable.
Stats
1-var, P&C
Non-decimal
base 2/8/10/16, logic ops, memories unavailable
Memory
28, continuous
Conversions
D/R/G, R/P, H/HMS, fraction TO decimal
Comments
Made by ?. Yet another take on the 2-line scientific calc design. PCB has 2001 design date. See applicable HP-30S notes re equation-entry type calcs. Operation for monadic prefix operators (like sqrt) on the current result is NOT improved: one needs to press SHIFT, ANS, EXE. Unusually for this type, the unit maintains NO history stack (well, one line!). Has engineering mode. Although the design is nice, uses soft rubber keys, and is sleekly PDA-like, I don't like the key layout too much. Shift, On/Clr and Exp are in weird places, and it's too easy to turn the machine off. The pre-programmed formulas range in complexity from Ohm's law, πr^2 and E=mc^2 to the cosine theorem and sums of progressions. They can be executed using values already in the memories or prompt for each. There are ten physical constants available from the keyboard. Can handle 11-digit octal numbers and 32-bit binary! "Block" scrolls between fields. Foren(1)=1.00000000055375750875202 - very close to the HP-30S but not identical.


Notes:

LR44 aka A76 aka AG13
L1131 aka G10
LR43, LR621, 2025, 2032, 2325, 2335

Watch out for Chinese button cells. The quality of most over the last few years has been abysmal. I've seen store displays of cheap trinkets where over half the batteries were corroded!


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© 2004 Michael Dunn