**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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