Thursday, September 21, 2017

Retro Review: Sharp EL-506G

Retro Review:  Sharp EL-506G


Company:  Sharp
Type:  Scientific
Year: 1992
Battery:  LR44 x 2, back case is screwed in
Digits: 10
Memory Registers: 7 (A, B, C, D, X, Y, M).  M is the independent register and is the only register available in all calculator modes.  Storage arithmetic commands M+ and M- are included. 
Type of Entry:  Algebraic (called D.A.L. for Direct Algebraic Logic by Sharp)

Thank you for Bob Patton.  I won this calculator as one of the door prizes on last week’s HHC 2017 (a post will be coming shortly).

I am going to describe the features by the modes available on the calculator.

Mode 0: Normal Mode

This is the normal mode where most of the mathematical operations are available.  Here you can convert integers to and from decimal, binary, octal, and hexadecimal mode.  The maximum binary number is 511 (2^9 – 1), and binary numbers are 10 bits including a signed bit (leftmost).  In binary, octal, and hexadecimal sub-modes, the Boolean functions NOT, AND, OR, XOR, and XNOR are available.

It is also in this mode where you can enter and work with fractions.  Fraction parts are separated by a small “r”.  Unfortunately, you cannot convert directly from decimal approximation to fractions.

A wild thing about the algebraic operating system is the display.  Most calculators will have you type the full expression on one line and give the answer on the second.  The EL-506G is however, one line.  Yes, you still enter expressions as you would write them but there is no way to go back and edit them.  During calculation, the function name or symbol will appear on the left hand the screen.  Multiplication is shown by *, and division is shown by /.  Implied multiplication is allowed, indicated by (*).  It takes a little getting used to.

On the EL-506G, Implied Multiplication gets higher priority than multiplication used by the multiply key [ x ].  So:

6 / 2 ( 1 + 2 ) = returns 1


6 / 2 * (1 + 2) = returns 9.

I like how the percent key works on the EL-506G, allowing to chain multiple calculations. 

Conversions and Constants

The EL-506G has 32 constants and 32 conversions.  If you have an EL-506G and need a listing, please email me at

Mode 1:  Complex Mode

The typical set of functions available for complex mode are present: arithmetic, 1/x, and x^2.  The [a b/c] key is mapped to i (√-1), while the [D°M’S] key is mapped to .

Complex mode has two sub-modes: rectangular and polar.  You can convert and change sub-modes by the use of the [→rθ] key.  [→rθ] converts to polar, while the shifted function ([2ndF] (→xy)) converts to rectangular.

Mode 2: Simultaneous Equations – Linear Systems

This modes solves 2 x 2 or 3 x 3 systems.  The matrix is set up as follows:

Ax = B where

A = [ [a1, b1, c1] [a2, b2, c2] [a3, b3, c3] ], B = [ [ d1 ] [ d2 ] [ d3 ] ]

For 2 x 2 systems, set a3, b3, c1, c2, c3, and d3 all to zero. 

For each linear system solved, the determinant of A is also calculated.

Mode 3:  Statistics Mode

When entering statistics, you will be asked to choose a model:

0 (SD):  1 Variable Statistics
1 (a+bx):  Linear Regression, y = a + bx
2 (…+cx^2):  Quadratic Regression, y = a + bx + cx^2
3 (e^x):  Exponential Regression, y = a * e^(bx)
4 (ln x): Logarithmic Regression, y =  a + b ln x
5 (a*x^b): Power Regression, y = a * x^b
6 (1/x): Inverse Regression, y = a + b/x

The [ STO ] key is mapped to the comma to enter bivariate data.
The [ M+ ] is for data entry.
The [ 2ndF ] (M-) is to erase data.


The keyboard feels quite nice, as the keys require a light touch.  Everything is very responsive. 

Final Verdict

The only tick I have is that the lack of editing algebraic expressions, when you only have one line to work with.  Other than that, this calculator is enjoyable to use.


I have two more retro reviews in the upcoming weeks:  TI-35 Plus and Radio Shack EC 4000 (TI-57 clone).  I also can’t wait to share with you what went on during HHC 2017.

It is a year off from next, but if you want to spend a weekend and have a massive geek, calculator, and math fest all rolled into one, the HHC 2018 will be next September.  I have so much fun at these conferences!  Please bug me as new information become available.

This blog is property of Edward Shore, 2017.

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