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
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: Orange New price: Display color: Black Display technology: Gas discharge display Size: 9½"×6½"×2½" Display size: 10+2 digits Weight: 3 lbs Entry method: Algebraic Batteries: 4×"D" internal NiCd Advanced functions: Floating point base-8, 10, 16 External power: TI adapter Memory functions: N/A I/O: N/A Programming model: N/A Precision: 12 digits Program functions: N/A Memories: N/A Program display: N/A Program memory: N/A Program editing: N/A Chipset: Forensic result:

If you look closely, you might just be able to discern a strange number on this calculator's display: 3.243F6A888. No, it's not a faulty device. Yes, that is the value of π. How come, you ask? Well, the SR-22 is a very unique device: possibly the world's only electronic calculator that is designed to do integer and floating point arithmetic in three number bases, decimal, octal, and hexadecimal.

This absolutely unique device was part of Texas Instrument's first series of calculator offerings. Although not a programmable machine, it is definitely a programmer's tool, and thus it has a place in this collection. Even if its beautiful Panaplex display didn't warrant it, how could I possibly resist a calculator that can be used to compute the factorial of AAhex and correctly display the result: A.55bC32206expFE?

And in case you wanted to know (I did), the value of e in hexadecimal is 2.B7E1516280C. Computing it (or indeed, the exponential of any number) is easy even on a four-banger. The formula to use is this:

$e^x=\frac{x^0}{0!}+\frac{x^1}{1!}+\frac{x^2}{2!}+...$

This series converges quickly, and on an algebraic calculator with no precedence logic, it can be computed very easily. On the SR-22, once you put x into memory using STO, you can then proceed with the following keystrokes:

RCL ÷ 7 + RCL ÷ 6 + RCL ÷ 5 + RCL ÷ 4 +
RCL ÷ 3 + RCL ÷ 2 + RCL ÷ 1 + RCL =

Of course for greater accuracy, you can start with a number greater than 7; to compute e to 10+ hexadecimal digits, I started with Fhex.