Spotlight: TI-32 Solar from 1988

Spotlight: TI-32 Solar from 1988

Today’s spotlight is on a standard scientific calculator from Texas Instruments… with a twist. First, let’s start with the quick facts.

Quick Facts

Model: TI-32 Solar

Company: Texas Instruments

Timeline: 1988 (possibly 1989?), this model was very short lived

Type: Scientific

Memory: 1 memory register

Power: Solar

Screen: 10 digits

The TI-32 Solar was a scientific calculator that was sold briefly by Texas Instruments in the last 1980s. The function set is a combination of the TI-30 Solar and the original one line TI-34:

* trigonometry, decimal/dms conversion, rectangular/polar conversions

* logarithms, anti-logarithms (10^x, e^x), powers

* one variable statistics (mean, deviation, sums)

* binary/decimal/hexadecimal conversion (and just conversions, strangely no octal)

* 3-decimal random number generator (RND)

* percent function

The Polar/Rectangular conversions use the [ a ] and [ b ] keys. [ a ] is for x and r, while [ b ] is for y and Θ.

The statistics mode is one-variable only. Though I am not a fan of the STAT mode being the alternative function of the [ C ] key, thankfully, the stat mode works.

What truly sets the TI-32 Solar apart are two things:

(1) The orange trim and keys on a dark gray keyboard. This is a very rare color scheme, especially orange until Texas Instruments started to release the TI-30XIIS and the TI-84 Plus CE in various colors.

(2) The screen tilts. The screen is a set on a hinge that allows the user to tilt the screen to different angles, which allows for more ergonomic operation. To put the calculator away, tilt the screen to be aligned with the keyboard and use the slide case. I think this is a really neat idea. The tilt mechanism seems to hold out well for a nearly 40 year old calculator.

Source

Woerner, Joerg. “Texas Instruments TI-32 SOLAR” Datamath Calculator Museum. September 20, 2002. Accessed July 7, 2025. http://www.datamath.org/Sci/Modern/TI-32Solar.htm

Eddie

 All original content copyright, © 2011-2025. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

All posts are 100% generated by human effort.  The author does not use AI engines and never will.

Casio fx-3900Pv: Linear System, Poisson Kernel, Normal Distribution, 3 x 3 Matrix Determinant

Casio fx-3900Pv: Linear System, Poisson Kernel, Normal Distribution, 3 x 3 Matrix Determinant

Today, we feature four programs for the classic Casio fx-3900Pv calculator. The fx-3900Pv has 300 steps.

My review from 2023: https://edspi31415.blogspot.com/2023/05/retro-review-casio-fx-3900pv.html

One of the great features of the early “inexpensive” algebraic keystroke programmable calculators (1980s) is that the programs can be seen and edited.

The programs listed will require inputs to be stored in to the memory registers prior to running the program by using the [ Kin ] key.

Casio fx-3900Pv: 2 x 2 Systems

This program solves 2 x 2 linear systems. The Constant memory registers (K1 – K6) are mapped as follows:

K4 * x + K5 * y = K6

K1 * x + K2 * y = K3

The equations are solved as follows:

x = (K2 * K6 – K5 * K3) / M

y = (-K1 * K6 + K4 * K3) / M

where M = (K4 * K2 – K1 * K5)

This program takes 36 steps.

Code:

Kout 4 (determinant)

×

Kout 2

-

Kout 1

×

Kout 5

=

Min

HLT (Pause program, shows determinant. We want a nonzero-determinant.)

(

Kout 2

×

Kout 6

-

Kout 5

×

Kout 3

)

÷

MR

=

HLT (Solve for x)

(

Kout 1

+/-

×

Kout 6

+

Kout 4

×

Kout 3

)

÷

MR

= (Solve for y)

Examples

Example 1

x – y = 5

x + 3 * y = 9

Store the parameters: 1 Kin 4, -1 Kin 5, 5 Kin 6; 1 Kin 1, 3 Kin 2, 9 Kin 3

Results: det = 4, x = 6, y = 1

Example 2

3 * x + 16 * y = 49

5 * x – 2 * y = 22

Store the parameters: 3 Kin 4, 16 Kin 5, 49 Kin 6; 5 Kin 1, -2 Kin 2, 22 Kin 3

Results: det = -86, x = 5.23255814, y = 2.081395349

Casio fx-3900Pv: Poisson Kernel

The program calculates the kernel using the formula:

Pr(θ) = (1 – r^2) / (1 – 2 * r * cos θ + r^2),

0 ≤ r < 1, -π < θ ≤ π

This program takes 22 steps.

Store r in register 1, θ in register 2.

Code:

Rad (Mode 5)

(

1

-

Kout 1

x^2

)

÷

(

1

-

2

×

Kout 1

×

Kout 2

cos

+

Kout 1

x^2

)

=

Examples

Example 1:

r = 0.5, θ = 2.1

0.5 Kin 1, 2.1 Kin 2

Result: 0.4273879049

Example 2:

r = 0.268, θ = 0.842

0.268 Kin 1, 0.842 Kin 2

Result: 1.298397221

Source:

“Poisson Kernel” Wikipedia. May 28, 2024. https://en.wikipedia.org/wiki/Poisson_kernel

Retrieved November 26, 2024

Casio fx-3900Pv: Normal Distribution (Integration)

The program, which is ran in Integration Mode (Mode 1):

∫( e^(-t^2 / 2) / √(2 * π) dt, a, b)

To calculate, really approximate the integral:

MODE 1 P#

Store a level n (1-9), SHIFT RUN

Lower limit RUN

Upper limit RUN

The level n corresponds to the integration intervals 2^n. The higher n is, the longer the calculation takes but the accurate the integral is.

The integrated variable is stored in memory M. Start the function using Min.

Code:

Min

(

MR

x^2

+/-

÷

2

)

e^x

÷

(

2

×

π

)

√

=

Examples

The following examples will use n = 4.

Example 1: lower limit = 0, upper limit = 3. Result: 0.49865

(actual ≈ 0.4986501019)

Example 2: lower limit = -1, upper limit = 1. Result: 0.6827

(actual ≈ 0.6826894921)

Example 3: lower limit = -2, upper limit = 1.5. Result: 0.910443

(actual ≈ 0.910 4426667)

Casio fx-3900Pv: 3 x 3 Determinant

This program calculates the determinant of a 3 x 3 matrix. How are we to do this with only seven memory registers?

The program sets the matrix as:

[ [ 1^st input, 2^nd input, 3^rd input ] [ K4, K5, K6 ], [ K1, K2, K3 ] ]

The user will be stop execution three times. At each time, enter the element corresponding to the top row.

For example:

[ [ 1, 2, 3 ] [ 4, 5, 6 ] [ 7, 8, 9 ] ]

Store 4 in K4, 5 in K5, 6 in K6; 7 in K1, 8 in K2, 9 in K3. While running, enter 1, 2, then 3 during program execution.

The determinant is stored to memory M. This program takes 40 steps.

Code:

(

Kout 5

×

Kout 3

-

Kout 2

×

Kout 6

)

×

ENT # (enter a legitimate number to continue, prompt for row 1, column 1)

=

Min

(

Kout 4

×

Kout 3

-

Kout 6

×

Kout 1

)

×

ENT # (prompt for row 1, column 2)

=

M-

(

Kout 4

×

Kout 2

-

Kout 5

×

Kout 1

)

×

ENT # (prompt for row 1, column 3)

=

M+

MR

Examples

Example 1:

[ [ 1, 5, 6 ] [ 2, 7, 8 ] [ 11, 4, 3 ] ]

Store:

(2^nd row) 2 Kin 4, 7 Kin 5, 8 Kin 6

(3^rd row) 11 Kin 1, 4 Kin 2, 3 Kin 3

Run the program (P1-P4): 1 RUN, 5 RUN, 6 RUN

Result: -15

Example 2:

[ [ -3, 0, 9 ] [ 0 , -3, 9 ] [ 9, -3, 0 ] ]

Store:

(2^nd row) 0 Kin 4, -3 Kin 5, 9 Kin 6

(3^rd row) 9 Kin 1, -3 Kin 2, 0 Kin 3

Run the program (P1-P4): -3 RUN, 0 RUN, 9 RUN

Result: 162

Until next time,

Eddie

All original content copyright, © 2011-2025. Edward Shore. Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited. This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.

Sharp EL-5100 Programs

 Sharp EL-5100 Programs

We can use the formula programming engine of the classic Sharp EL-5100 (1979) to store multiple formulas and invoke some simple programs.

Quadratic Formula

ax^2 + bx + c = 0

x = (-b ± √(b^2 - 4ac)) / (2a)

Formulas (AER Mode):

1; f(A,B,C)=(B²-4AC) STO D ◣

2; (-B+√D)÷(2A STO E, (-B-√D)÷(2A STO F

Instructions (COMP Mode):

1.  Press [ 1; ], enter A, B, and C.   D is shown as ANS 1.  If D ≥ 0, then the polynomial have real roots.  Continue to the next step.  If D < 0, then the polynomial has complex roots, stop. 

2.  Press [ 2; ], the two roots are displayed.

Examples:

Example 1:  A = 1, B = -1, C = -3.75;  Results:  2.5, -1.5

Example 2:  A = 2, B = 26, C = 84; Results:  -6, -7

Power of a Complex Number (Principal)

(a + bi)^c  = d + ei   

The →POL stores θ in I and displays r, which r is not automatically stored.

Formulas (AER Mode):

1; f(A,B,C)=A →POL B STO I, I^C×COS(JC) STO D, I^C×SIN(JC) STO E

^ represents Y^X.  

Instructions (COMP Mode):

1.  Set the calculator to Radians mode.  Press [ 1; ]. 

2.  You get three results:  I  (r), real part, imaginary part.   Press [ COMP ] to see each result (ignore the first result)

Examples:

Example 1:  (4 + 4i)^3 = -128 + 128i;  r = 5.56854249

Example 2:  (5 - 6i)^0.5 = 2.5308348108 - 1.18537961766i;  r = 7.810249676

Confidence Interval

Here, we can use one formula to store values for use in the next formula.

confidence interval = A ± J * B / √C

where:

A = mean

B = variance

C = n

J = z*  (see table below)

z* values:

F:  99% confidence level, value = 2.576

G: 98% confidence level, value = 2.326

H: 95% confidence level, value = 1.96

I:  90% confidence level, value = 1.645

Formulas (AER Mode):

1;  2.576 STO F 2.326 STO G 1.96 STO H 1.645 STO I ◣

2;  f(A,B,C,J)=A-JB÷√C STO D, A+JB÷√C STO E

Instructions (COMP Mode):

1.  Initialize by pressing [ 1; ].  When the display says ANS1 = 0, the initialization is complete.

2.  Press [ 2; ], enter mean for A, press [ COMP ], enter variance for B, press [ COMP ], enter n for C, press [ COMP ], choose F, G, H, or I for J (confidence level), press [ COMP ].

Examples:

Example 1:

99% level with mean = 34.56, variance = 19.79, n = 53.  For 99%, enter F for J.

Result: 22.557490316, 41.562509684

Example 2:

90% level with mean = 100, variance = 12, n = 42.  For 90%, enter I for J.

Result:  96.9540518717, 103.045948128

Sum of a Function

On the EL-5100, we will have to manually keep track of the loop.

∑ f(I) from I=A to B (increment 1), result is stored in M.

Formula Template (AER Mode):

1;  f(I)= STO I, 0 →M ◣

2; [enter function here] M+, 1+I STO I

Instructions (COMP Mode):

1.  Press [ 1; ].  At the f(I)= prompt, store the lower limit.  Press [ COMP ] twice to complete the initialization.  

2.  Press [ 2; ].   The first result is f(I).  Press [ COMP ] to increase I by 1.  Repeat the pattern by pressing [ COMP ]. Do this until ANS2 > B (you need to keep track manually)

3.  Press [ RM ] to get the final result.

Example:  

∑( (I-2)×(I+6) ) for I=1 to 5

Setup (AER Mode):

1;  f(I)= STO I, 0 →M ◣

2;  (I-2)×(I+6) M+, 1+I STO I

[1; ] [COMP] [COMP]

[2; ] [COMP] [COMP]  ANS2 = 2

[2; ] [COMP] [COMP]  ANS2 = 3

[2; ] [COMP] [COMP]  ANS2 = 4

[2; ] [COMP] [COMP]  ANS2 = 5

[2; ] [COMP] [COMP]  ANS2 = 6

[ RM ]

Result: 55

Fun to explore different ways to solve problems, and play with retro calculators. 

Eddie

All original content copyright, © 2011-2021.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author. 

Retro Review: Casio fx-7400g Plus

Eddie’s Math and Calculator Blog:  Retro Review:  Casio fx-7400g Plus

Specifications

Time:  Early 2000s, I have the early style where all the keys are rectangular

Screen:  48 x 80 pixels, 6 x 13 text

Power:  2 AA batteries with 2032 backup

Accuracy:  10 digits shown on screen, 15 digits internally

Memory:  20,000 bytes for programming (despite the 32K label on the calculator)

The calculator feels pretty good to hold, it is lightweight.

A Scaled Down fx-9850g

The fx-7400g Plus is a simplified version of fx-9850g family, marketed as entry level graphing calculator.  The features have been scaled down.  As a result the fx-7400g Plus lacks matrices, distribution functions, numerical integral, and polar graphing.

Casio is known as for their icon menus and the fx-7400g is no exception.  Here is the icon menu:

1:  Run	2:  Statistics	3:  List
4:  Graph	5:  Table	6:  Program
7:  Link	8:  Contrast	9:  Memory

For statistics, the fx-7400g offers the following regressions:  linear, med-med, quadratic, logarithmic, exponential, and power.

Curiosities of the fx-7400g Plus

Instead of the usual six function keys (F1 – F6), the fx-7400g Plus has four function keys, with two of them replaced with [ G<>T ] (graph-table switch) and [ > ] (next menu page).  I don’t know if the [G<>T] key is used today, but it is used two switch between the graph and home screen.  Today, the command only works when the current Casio graphing calculators (like the Prizm fx-CG 10) is in the Linear Input/Output mode. 

When a program is executed, the calculator is returned to the Run mode rather than stay in Program mode.  Exit program execution by pressing [AC/ON].

When Program Mode is entered, all the programs are listed chronically (when they first created).  There is no option to sort the programs alphabetically.

The fx-7400g handles calculations pretty quickly. 

Programming on the fx-7400g Plus

The programming command set on the fx-7400g Plus may be scaled down, but most of the commands we expect on the Casio Graphing calculators are present.  The lack of matrices, complex numbers, and a simplified list command set does provide a challenge, but we should be able to program for a lot of applications.

To get the quotes ( “ “ ), press [ALPHA] then [ F2 ].  This is the only way to get the quotation marks.

Programming Commands Available (not exhaustive):

[“prompt”]?  → var ◢    (right triangle) :     (colon for multiple commands)

If Then [Else] IfEnd Cond ⇒ do if true: next Do commands LpWhile cond While cond commands WhileEnd Dsz  var:  do if var ≠ 0: stmts  (-1) Isz var:  do if var  ≠ 0:  stmts   (+1) Goto,  Lbl

Break   (break from loops) Prog “filename” (subroutines) Return Stop

ClrGraph ClrList ClrText DrawStat DrawGraph DrawTable

Fortunately any of the programs created on the fx-7400g Plus can be translated literally to later Casio graphing calculators. 

I will present programs on next blog entry.

Final Verdict

The fx-7400g Plus is not a bad entry-level calculator.  The early version is more an old-school graphing calculator. 

The updated fx-7400gII Casio now includes integral, polar graphing, base calculations, and complex numbers.  ( Link:  https://edu.casio.com/products/graphic/fx7400g2/ )

Happy Thanksgiving!

Eddie

This blog is property of Edward Shore, 2016.

Retro: A Quick Look at the TI-74 (and HHC 2016)

Retro:  A Quick Look at the TI-74 Basicalc

Back to the 1980s Again

Recently I purchased a Texas Instruments TI-74 Basicalc calculator.  The calculator came in great condition, including manuals and a Mathematics module (and the module). 

The TI-74 is a BASIC programming calculator (similar to Hewlett Packard’s HP-71B and HP-75 and Casio’s fx-795P).  The keyboard of the TI-74 is very busy and has a QWERTY keyboard.  The keys are nice but I am not able to type fast on it.  The calculator takes four AAA batteries.  The calculator I got was produced in 1985.  The original cost was around $130, which was a pretty good price for a basic portable BASIC computer/calculator at the time.  

HP 71B (top) and TI-74 (bottom).  The 74 is a giant!

The TI-74 is a BASIC programming calculator (similar to Hewlett Packard’s HP-71B and HP-75 and Casio’s fx-795P).  The keyboard of the TI-74 is very busy and has a QWERTY keyboard.  The keys are nice but I am not able to type fast on it.  The calculator takes four AAA batteries.  The calculator I got was produced in 1985.  The original cost was around $110-$130, which was a pretty good price for a basic portable BASIC computer/calculator at the time.  The one I got on Amazon, originally sold at Brendle's (a defunct chain store which was based in Elkin, North Carolina)

Calculator Mode vs. BASIC Mode

Modes are switched back and forth with the [ MODE ] toggle key.

Calculator Mode

Like the HP-71B, the TI-74 has two modes: Calculator and BASIC mode.  In Calculator mode, the QWERTY keyboard becomes a scientific calculator, with all the functions stated in blue.  For example, the [ S ] key is the angle change key [ DRG ], while the [ U ] key becomes the square key [ x² ].  In Calculator mode, the TI-74 operates as an AOS (Algebraic Operating System) calculator.  If have worked with a TI-30Xa or a classic TI-36X Solar, you should be familiar with it. 

The Display

The numbers are aligned to the right.  What is neat about the display is that the last function used will also be displayed.  For example:  cos(√19°):

Keys	Screen
[DRG] (S) to degrees mode	DEG is highlighted
19	19  |
[ √x ] (I)	4.358898944 | √x
[ cos ] (W)	.99710753 | cos

Two Argument Functions

One of the quirks about the Calculator mode is how two argument functions are operated.  For input, you will need to press [ (x,y) ] (the L key). 

Combinations and Permutations:  Enter n, press [ (x,y) ] (L), r and press either [ nCr ] (J) for combinations or [ nPr ] (H) for permutations. 

Polar to Rectangular:  Enter r, press [ (x,y) ] (L), then θ, [ P>R ] (F).  x is displayed first, press [x<>y] (RUN) to show y. 

Rectangular to Polar:  Enter x, press [ (x,y) ] (L), then y, press [ INV ] (SHIFT), [ P>R ] (F).  r is displayed first, press [x<>y] (RUN) to show θ. 

Strangely enough, this isn’t the percent change function works.  Enter the new amount, press [Δ%] (SPACE), then the old amount.  For example, if I wanted to find the percent change from 150 to 180, I would key in 180, [Δ%], 150, [ = ] to get 20. (20% increase)  This is also the same way of how to computer percent changes with the TI-55 III.

Statistics: Only Available in Calculator Mode

The statistics module of the TI-74’s calculator mode can handle either one-variable date or linear regression (y = a + bx).  You call statistical variables and clear its registers by first pressing the [ STAT ] (CTL) key.  All the statistical variables are marked in yellow.

BASIC Mode

By default, the TI-74 has 7,710 bytes of memory.  You can add a memory module that would affectively double the memory.  This is also where you can access any ROM module commands.

The language of the TI-74 is straight forward.  What is neat is that the case that comes with the TI-74 has syntax of the BASIC commands available card for reference. 

There is only one program space (similar to early keystroke calculators like TI-58C and HP-12) on which all the programming steps are shared, with no separate file management.  However, you are able to run the program space from any designated line number, so you can fit multiple routines on the TI-74.  You can designate the line numbers from 1 to 32766, and each line numbers can become multi-statement lines with the use of colons. (:)

 Over the course of the next month or so, I hope to post programs for the TI-74.  Here is one that I did as my first TI-74 routine (sum of f(x)):

100 INPUT “lower:”;L

105 INPUT “upper:”;U

110 T=0

115 FOR X=L TO U

120 GOSUB 150

125 T=T+F

130 NEXT X

135 PRINT “total=”;T:PAUSE

140 END

150 F=X^2   \\ or any f(X)

155 RETURN

Make sure all the routines have END, that stops execution.  The default case for the alpha keys in BASIC mode is lower case.  To get the upper case lock, press [SHIFT] [UCL]. 

The only thing I am not crazy about is that the BASIC functions are printed in gray and it can be hard to see when holding the TI-74 at different angles.

Mathematics Module

The Mathematics Module for the TI-74 is very sophisticated.  I haven’t had much time to play with the module, but the module provides the following functions:

* Complex functions (COMPF): Arithmetic, Logarithms, Powers, Trigonometric, Parts of the Rectangular and Polar forms.  This is really full-fledged, especially for complex numbers in the 1980s.

* Gamma Function (GAM)

* Polynomial Multiplication (POL):  This program calculates the coefficients of p(x) * q(x)

* Curve Analysis: Cubic Splines, Relative Minimum, Root Finder by either Bisection or Newton’s Method

* Calculus:  Convolution, Runge-Kutta (differential equations), Gauss Quadrature (integrals)

* Matrices: 3 x 3 systems including complex numbers, Matrices Utilities (addition, multiplication, inverse, simultaneous equation, determinant), Tridiagonal Solving routine

Peripherals

The TI-74 can be attached to a compatible printer or a module that allows programs to be recorded on cassettes. 

  

On a side note… HHC 2016!

I will be going to the HHC 2016 conference in two weeks (9/17 – 9/18/16) in Fort Collins, CO.

Site:  http://hhuc.us/2016/index.htm

Eddie

This blog is property of Edward Shore, 2016.