Radio Shack PC-5

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: Alphanumeric display  
New price:   Display color: Black  
    Display technology: Liquid crystal display 
Size: 6"×6"×½" Display size: 24 characters
Weight: 6 oz    
    Entry method: BASIC expressions 
Batteries: 2×"CR-2032" Lithium + 1×"CR-1220" Lithium Advanced functions: Trig Exp Hyp Lreg Cmem Snd 
External power:   Memory functions:  
I/O: Printer, memory expansion     
    Programming model: BASIC 
Precision: 12 digits Program functions: Jump Cond Subr Lbl Ind  
Memories: 4(0) kilobytes Program display: Text display  
Program memory: 4 kilobytes Program editing: Text editor  
Chipset: Casio fx-780P   Forensic result: 9.00000716758  

pc5.jpg (42370 bytes)The Tandy/Radio Shack PC-5 is a BASIC programmable handheld calculator. If you think you've seen it under another name, you're not mistaken: it is really a Casio model, the Casio fx-780P to be precise.

I was never too fond of folding-design calculators. True, their design protects the display and helps keep the keyboard clean. On the other hand, the design tends to be fragile, and one-handed operation is more difficult. To Casio's credit, the flexible ribbon connections between the two halves (just like the flexible ribbon connectors that are used internally, for instance with the LCD display) tend to be very reliable. If only the same thing could be said about other models, including some brand-name calculators from the likes of TI or Sharp!

The following program, computing the Gamma function to a high degree of precision, demonstrates the programming model of this calculator:

20 Z= ABSX
30 G=1
40 IF Z>9 THEN 80
50 G=G*Z
60 Z=Z+1
70 GOTO 40
80 G=( LNZ+ LN SQR(Z* HYP SIN(1/Z)+1/810/Z^6)-1)*Z-LNG
90 G=G+ LN SQR(2*π/Z)
100 IF X>0 THEN 120
110 G= LN(-π/X/ SIN(π*X))-G