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: Black  
    Display technology: Liquid crystal display 
Size: 5"×3"×¼" Display size: 10(8+2) digits
Weight: 2 oz    
    Entry method: Algebraic with precedence 
Batteries: 2×"V389" button cell Advanced functions: Trig Exp Hyp Sdev Cmem 
External power:   Memory functions:
    Programming model: Partially merged keystroke 
Precision: 11 digits Program functions:  
Memories: 3 numbers Program display:  
Program memory: 40 program steps Program editing:  
Chipset: Sharp LI3301A   Forensic result: 9.0000156204  

[NB: One user reports that his PR-100 is powered by a single CR2016 lithium button cell.]

npr100.jpg (30699 bytes)I am holding in my hands a calculator that manages to be most unusual and most common, all at the same time.

It is unusual because it is the first ever programmable calculator I've seen under the NOMA brand name, and also the first out of Poland (at least I believe that Kalkulator programowalny, seen on the machine's back label, is Polish for programmable calculator.) Although I do not know the precise date of its manufacture, some of its characteristics, such as the hand-written serial number on the back, or the green wax warranty seal over one of the (flatblade, not Phillips) screws suggest that it was still manufactured in a factory owned by the Communist state, or perhaps was made shortly after the transition to a market economy. [Update: a user reports that his PR-100 was manufactured in December 1989.]

So what makes it common, then? It uses a calculator chip that is perhaps the most widely used in OEM or store label programmable calculators world-wide. Right at this moment, I am staring at a collection of no fewer than fourteen different calculators (two Citizens, an Aurora, a Privileg, an MBO, an Ibico, an MCI, a Knight, an Intertronic, a PiraComp, two Radio Shacks and a Walther brand machine in addition to this NOMA PR-100), all of which appear very different, all of which are functionally identical, having the same Sharp LI3301A calculator chip inside.

The programming model of this calculator chip is rather limited. Only 40 steps are available, fewer if you use the calculator's memories. No conditionals or branching, and you have to cope with that dreaded "feature" of the X-register being zeroed out whenever you switch to Learn mode, making it impossible to enter an algorithm that yields an error for a null argument.

Even so, the calculator has enough "juice" for a low accuracy implementation of the Gamma function using Stirling's formula: