Qualitron 1421 Programmable Scientific
| Datasheet legend
Ab/c:
Fractions calculation
AC: Alternating current BaseN: Number base calculations Card: Magnetic card storage Cmem: Continuous memory Cond: Conditional execution Const: Scientific constants Cplx: Complex number arithmetic DC: Direct current Eqlib: Equation library Exp: Exponential/logarithmic functions Fin: Financial functions Grph: Graphing capability Hyp: Hyperbolic functions Ind: Indirect addressing Intg: Numerical integration Jump: Unconditional jump (GOTO) Lbl: Program labels LCD: Liquid Crystal Display LED: Light-Emitting Diode Li-ion: Lithium-ion rechargeable battery Lreg: Linear regression (2-variable statistics) mA: Milliamperes of current Mtrx: Matrix support NiCd: Nickel-Cadmium rechargeable battery NiMH: Nickel-metal-hydrite rechargeable battery Prnt: Printer RTC: Real-time clock Sdev: Standard deviation (1-variable statistics) Solv: Equation solver Subr: Subroutine call capability Symb: Symbolic computing Tape: Magnetic tape storage Trig: Trigonometric functions Units: Unit conversions VAC: Volts AC VDC: Volts DC |
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Qualitron 1421 Programmable Scientific
What an unusual little calculator this is! This calculator has apparently been sitting in its retail box for the last 25 years or so. I never even heard about this model until one day it appeared on eBay. It turns out to be a functional equivalent of the Novus Mathematician PR (4515) with the same features and limitations. It has generous program storage capacity (102 unmerged program steps) but the machine's utility is limited by the fact that it has only 1 memory register, a 3-level stack, no exponential display (!), and no control transfer or conditional execution capability.
Even so, it's a useful machine. It has a very pleasing, large, bright LED display, somewhat unusual for calculators of this era. Overall, the machine gives a pleasing, robust feel and appearance, with a good quality plastic case and snappy keyboard.
Demonstrating the calculator's programming model, the program below is yet another implementation of my favorite programming example, the Gamma function. Using a variant of Stirling's formula, this method yields 7+ digits of precision calculating the natural logarithm of the Gamma function of any positive argument.
ENTER 5 + MS ln MR × MR - π 2 × MR ÷ ln 2 ÷ + 1 2 1/x MR ÷ + 7 2 1/x 5 ÷ MR ÷ MR ÷ MR ÷ - 2 5 2 1/x 5 ÷ MR ÷ MR ÷ MR ÷ MR ÷ MR ÷ + 1 M- C MR 1 M- C MR × 1 M- C MR × 1 M- C MR × 1 M- C MR × ln -
