Sharp EL-5120

• 3-line alphanumeric LCD display.
• Alphanumeric keyboard with SHIFT and ALPHA keys.
• All the standard trigonometrical functions (SIN, COS, TAN) as well as their inverse and hyperbolic versions.
• All of the standard power raising, logarithmic etc. functions
• Some functions like statistical operations and boolean logic functions are accessed via sub-menus, and thus they are not printed on any visible key.
• 28 global user variables (A through Z plus ANS and θ), stored in CMOS memory.
• Up to 9 local variables for each mode of operation and equation, solver or program file, with user defined names. Unlike the 28 global ones, using these local variables consumes user RAM.
• 1 and 2 variables statistics, has only a simple linear regression analysis.
• File "saving", "loading" and "deleting" from the small user RAM. Each mode can store its own "files", containing e.g. the last calculation or expression, a solver equation or a program plus any eventual local variables and the last ANS value.
• Expression evaluator (in Real mode).
• Numerical integration using Simpson's rule.
• Numerical equation solver vs a specific variable using Newton's method.
• Programs and solver equations can "exchange data" between them by appropriate use of the global variables, for solving more complex problems.
• Adjustable contrast.
• Uses one 3V CR2025 lithium battery.

• Lack of built-in support for complex numbers (can only be emulated via a program or equations).
• Programs and equation files eat up RAM quickly, especially if they contain local variables.
• Local program variables cannot be removed once added without deleting the program.
• Integration/solver functions can be slow or erratic.
• Only one kind of statistical regression (linear).
• Lack of any built-in application formulae or physical constants, these have to be defined and saved by the user as expression and local variables, with a notable expense of RAM.
• Lack of some built-in functions like a simultaneous linear equations system or second grade equations solver, thus forcing to implement them by programming.
• The programming language used consumes RAM too quickly due to weak construction, lacking a proper FOR-like statement and thus forcing to use long and costly LABEL, GOTO and GOSUB statements.

Please note that the actual notation might be different, as some special EL-5120 characters cannot be directly typed on a PC, e.g. the square root and fraction operator:

 Hello world:

 HELLO: REAL
 LABEL 10
 PRINT"HELLO WORLD
 GOTO 10

 Solver of second grade equations:

 GRADE2:REAL
 INPUT A
 INPUT B
 INPUT C
 D=B²-4AC
 IF D<0 GOTO ERR
 X=(-B-sqrt(D))/(2A)
 Y=(-B+sqrt(D))/(2A)
 PRINT X
 PRINT Y
 GOTO E
 LABEL ERR
 PRINT D
 LABEL E
 END

 Calculate ICE current and VCE voltage for a BJT transistor, 
 using the 4-resistor polarization method.

 Note: These local variables must be defined first:
   R1,R2,R3,R4,B0=gain ,V8=0.7 or 0.3 (base voltage in V for silicon or germanium BJTs, accordingly)

BTJ-4R:REAL

INPUT R1
INPUT R2
INPUT R3
INPUT R4
INBUT B0
INPUT V
R=R1R2/(R1+R2)
T=VR2/(R1+R2)
I=(T-V8)/(R+(B0+1)R4)
C=V-I(B0R3+(B0+1)R4)
I=B0I
PRINT I
PRINT C

• The EL-5120 on Sharp's website