Elektronika B3-21 (VFD)
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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Elektronika B3-21 (VFD)
The first Soviet programmable calculator, the B3-21, came in two versions. More common is the one with a red LED display; however, machines were also produced using a green vacuum fluorescent display tube.
Why, I wonder? Based on the fact that most subsequent Soviet models used vacuum fluorescent displays, and based further on the fact that the LED modules in my B3-21s appear to be Western made, a possible explanation presents itself: in an economy starved for hard currency, solutions were favored that could replace Western imports with domestically produced parts.
Apart from the display, my newest B3-21 is identical in all respects to the red LED version. This even includes the way the display is utilized. Perhaps uniquely among VFD machines, the "green" B3-21 reserves a full digit position for the decimal point, and accordingly, the decimal point is placed in the center of the lower half of the 7-segment digit, as in HP LED display modules.
When I first wrote about the B3-21, it seemed to me that its somewhat ineffective programming model (a most annoying "feature" is the lack of an automatic stack lift before register retrievals) makes it impossible to write a useful implementation of my favorite example, the Gamma function. This is not so. Stirling's formula can, in fact, be used to write a program that computes the logarithm of the Gamma function 6+ digits of precision for all positive and negative arguments. This program uses a simple iteration to compute the result for arguments smaller than 5; consequently, for negative arguments with a large magnitude, the algorithm can be slow. For positive and small negative numbers, however, the algorithm is reasonably fast (this is a mighty slow machine!) and accurate.
01 06 ^ 02 21 P 2 03 14 1 04 41 P 4 05 16 x-y 10 58 8 11 86 - 12 69 x<0 13 32 32 [F 3] 14 42 F 4 15 26 × 20 41 P 4 21 16 x-y 22 14 1 23 96 + 24 21 P 2 25 06 ^ 30 58 BP 31 06 06 [^] 32 22 F 2 33 06 ^ 34 13 ln 35 26 × 40 86 - 41 31 P 3 42 23 π 43 24 2 44 26 × 45 06 ^ 50 22 F 2 51 36 ÷ 52 65 √ 53 06 ^ 54 42 F 4 55 36 ÷ 60 13 ln 61 06 ^ 62 32 F 3 63 86 - 64 31 P 3 65 34 3 70 04 0 71 45 1/x 72 06 ^ 73 22 F 2 74 55 x^2 75 36 ÷ 80 56 /-/ 81 14 1 82 96 + 83 06 ^ 84 22 F 2 85 36 ÷ 90 14 1 91 24 2 92 36 ÷ 93 06 ^ 94 32 F 3 95 96 + −0 78 C/П