Retro Review: Texas Instruments BA-Solar
Finance + Solar + 1980s
Company: Texas Instruments
Years: 1986 - 1990s; a refresh , BA-35 SOLAR was produced 1996-2000s
Operating Modes: Chain
Number of Registers: 1, |MEM|
Display: 1 line, 10 digits
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
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:
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
Natural logarithm and antilogarithm: ln x, ^x
Square and square root
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.
Woerner, Joerg. "Texas Instruments BA-SOLAR" Last Updated December 5, 2001. http://www.datamath.org/Sci/Modern/BA-SOLAR.htm Retrieved May 19, 2022.
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