PTK-1060

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
Years of production:   Display type: Numeric display  
New price:   Display color: Red  
    Display technology: Light-emitting diode 
Size: 7½"×4"×2" Display size: 8+2 digits
Weight: 12 oz    
    Entry method: Reverse Polish Notation 
Batteries: 4×"D-0.55C" NiCd button Advanced functions: Trig Exp 
External power: Elektronika BP2-3 adapter   Memory functions:  
I/O:      
    Programming model: Keystroke entry 
Precision: 8 digits Program functions: Jump Cond Subr  
Memories: 8 numbers Program display: Keycode display  
Program memory: 60 program steps Program editing: Overwrite capability  
Chipset: Elektronika B3-21   Forensic result:  

ptk1060.jpg (41301 bytes)A PTK-what? 1060? What kind of a calculator is it? Imagine my surprise when my friend Gabor from Hungary sent an e-mail, attached to which was the photograph of this incredible find: a Hungarian OEM version of the first Soviet programmable calculator, the B3-21, with Western labeling.

The calculator is now in my possession and I can confirm that it is, indeed, a B3-21 in every respect, including the unusual rechargeable battery pack. One curious fact I noticed only after I received an inquiry from Sergei Frolov: all the keys with Western markings are painted, as opposed to the injection-molded language-neutral (or Cyrillic, on the original B3-21) keys.

The machine was in poor condition mechanically, but the 25-year old electronics still work like new, and I was able to repair the damage to the plastic housing. All in all, this machine reinforces the opinion I have of early Soviet calculators: unique, and surprisingly well engineered machines!

Well designed, too. Sure it has some shortcomings and idiosyncrazies (a two-level stack with no automatic stack lifting probably the most annoying among these) but even so, these machines feel eminently useful. The design is of quality, too, in more ways than one: the implementation of non-algebraic functions is accurate, the hardware design is clean, obviously meant for mass production under less than ideal circumstances by an insufficiently skilled labor force.

The bottom line is that after 25 years, these machines still work reliably.

When I first wrote about the B3-21, it seemed to me that its somewhat ineffective programming model makes it impossible to write a useful implementation of my favorite example, the Gamma function. Later, when I got my hands on a B3-21 with a green vacuum fluorescent display, I found out that I was wrong: 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. It is this program that is reproduced below as a programming example for the PTK-1060.

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