## Thursday, September 21, 2017

### Retro Review: Texas Instruments TI-35 PLUS

Retro Review:  Texas Instruments TI-35 PLUS

Essentials

Company:  Texas Instruments
Type:  Scientific
Year: 1986
Battery:  A76 x 2
Digits: 10
Memory Registers: 3, 2 temporary for certain functions and 1 permanent. Storage arithmetic commands SUM and EXC are included.

Thank you for Bob Patton.  I won this calculator as one of the door prizes on last week’s HHC 2017.

Like the last retro review, I am going to describe the features by the modes available on the calculator.

Mode 1: Decimal Mode (Normal)

This is the normal mode where most of the mathematical operations are available.
The [ a ] and [ b ] keys are temporary registers for various functions, such as:

Number of Combinations:  n [ a ], r [ b ], [ 2nd ] [ ÷ ] (nCr)
Number of Permutations:  n [ a ], r [ b ], [ 2nd ] [ * ] (nPr)
Rectangular to Polar Conversions:  x [ a ], y [ b ], [ 2nd ] [ b ] (R>P); r stored in [ a ], θ stored in [ b ]
Polar to Rectangular Conversions: r [ a ], θ [ b ], [ 2nd ] [ a ] (P>R); x stored in [ a ], y stored in [ b ]

Mode 2:  Binary Mode

Entering Binary Mode converts the number into a binary integer.  Arithmetic operations are available.  The maximum binary number is 511 (2^9 – 1), and binary numbers are 10 bits including a signed bit (leftmost).

Mode 3:  Octal Mode

Entering Octal Mode converts the number into an octal integer.  Arithmetic operations are available.

Entering Hexadecimal Mode converts the number into a hexadecimal integer.  Arithmetic operations are available.  In this mode, the [ sin ], [ cos ], [ tan ], [ 1/x ], [ a ], and [ b ] are remapped to the hexadecimal digits A, B, C, D, E, and F, respectively.

Bob Patton gives this amazing demonstration of the Hexadecimal mode:

[MODE] 4 [ tan ] [ 0 ] [ b ] [ b ] [ a ] [ a ] [STO]  (stores COFFEE_16 in memory)
[ tan ] [ 0 ] [ tan ] [ 0 ] [ sin ]  (inputs COCOA_16)

Repeat:
[ SUM ] [ 0 ] [ RCL ] [ = ] [ SUM ] [ +/- ]
(Note what happens while repeating this loop.  You can try a similar key stroke loop on similar calculators.  Thank you, Bob!)

Mode 5:  Complex Number Mode

Store the real part in temporary register [ a ], the imaginary part in temporary register  [  b ].  Arithmetic operations and polar/rectangular conversions are available.  Other math functions work on the components only.

Mode 6:  Statistics Mode

The TI-35 Plus offers 1-variable statistics with the standard measurements of mean, standard deviation (σn-1), population deviation (σn), and sums. The only way to clear the stat data is to exit stat mode, then enter it again.

An added feature is the three normal distribution probability functions.  Strangely, these functions do not rely on the data entered in the stat registers, and assume that the standard parameters apply (mean is zero, variance is one).

P(t):  lower tail probability
Q(t):  upper tail probability
R(t):  probability from 0 to z

Keyboard and Display

The keys are nice and responsive.  Over time the key markings wearing off.  I like the white font on the dark gray keys.  I wish there was a little more contrast for the secondary functions, which are black on dark gray.

The display is nice and crisp.

Final Verdict

I like the TI-35 Plus, it is a step up from the TI-30 series by adding complex number arithmetic and integer conversions.  However, the TI-35 Plus lacks the Boolean functions found on the TI-34.  It is a matter of what features are desired.

Eddie

This blog is property of Edward Shore, 2017.