Monday, June 27, 2022

Retro Review: Texas Instruments BA-Solar

Retro Review: Texas Instruments BA-Solar








Finance + Solar + 1980s


Quick Facts


Model:  BA-Solar

Company:  Texas Instruments

Years:  1986 - 1990s; a refresh , BA-35 SOLAR was produced 1996-2000s

Type:  Finance

Batteries: Solar 

Operating Modes:  Chain

Number of Registers: 1, |MEM|

Display:  1 line, 10 digits


Features


The [ MODE ] key is used to toggle between three modes:


FIN Mode:  Time Value of Money  (FIN indicator)


N:  number of payments

%i:  periodic interest rate

PV:  present value

PMT:  payment

FV:  future value


The current cash flow convention is not used, instead the following equation is (I think) used in solving time value of money calculations: 


PV = FV *  SPPV + PMT * USPV

SPPV = single present value factor

USPV = present value annuity factor


We also have amortization functions:


BAL:  balance after any payment

I/P:  interest and principal at any payment

payment_1 P1/P2 payment_2 I/P:  cumulative interest and principal


There are ×12 and ÷12 aids, but we still have to press [ N ] and [ %i ] to register the values, they are not automatic.  


STAT Mode:  Statistics  (STAT indicator)


The BA-SOLAR (and the later BA-35 SOLAR) has both single variable statistics and linear regression.


In linear regression, use the [x<>y] key to change between x and y.   The key will also be used to switch between results.  


Prediction values can be calculated with x' and y'.


The equation used for linear regression is y = a*x + b,  a = slope, b = intercept.


Profit Mode (no indicator)


The profit mode makes the following solver available:


CST:  cost

SEL:  sell

MAR:  margin

MU:  markup


Functions Available in All Modes


Percent Calculations (%):

Add %:  x [ + ] y [ % ] [ = ]

Subtract %:  x [ - ] y [ % ] [ = ]

Multiply %:  x [ × ] y [ % ] [ = ]

Percent Ratio:  part [ ÷ ] whole [ % ] [ = ]

Percent Change:  new [ 2nd ] ( ⊿% ) old [ = ]


rate >EFF payments/year:  convert to effective rate

rate >APR payments/year:  convert to APR/nominal rate


Mathematics:

Natural logarithm and antilogarithm:  ln x, ^x

Square and square root

Power

Reciprocal


Final Thoughts


This is a great basic financial calculator.  I have both the BA-SOLAR and BA-35 SOLAR.   To be honest, I like the keyboard of the original BA-SOLAR better, the keys feel a bit more solid and responsive.  Even though they are no longer in production, the BA-SOLAR is still reasonably available on sites such as eBay and other online stores.  


Source:


Woerner, Joerg.  "Texas Instruments BA-SOLAR"  Last Updated December 5, 2001.   http://www.datamath.org/Sci/Modern/BA-SOLAR.htm   Retrieved May 19, 2022.


Eddie


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