Sunday, January 5, 2020

Retro Review: Sharp EL-506A

Retro Review: Sharp EL-506A

Quick Facts:

Model:  EL-506A
Company:  Sharp
Type:  Scientific
Years:  Introduced 1985
Display:  10 digits
Batteries:  Battery, 1.5 V. 

Special thanks to Tom Manning for furnishing this calculator.  Much appreciated. 

The calculator comes in a compact folding wallet. 


The available modes are:

Decimal Mode:  This is the normal scientific calculator mode. 

The EL-506A has two memory registers, M1 and M2.   There are three keys dedicated to the memory registers:  [ x→M ] (store), [ RM ] (recall), and [ M+] (storage addition).  Memory 1 is the primary key while memory 2 is the secondary key.  Contents of the memory registers are retained even when the calculator is turned off. 

Complex Mode:  Use the [ a ] and [ b ] keys for complex number arithmetic calculations.  Rectangular and Polar conversions are included in this mode ( →xy, →rθ).  Complex mode is toggled on and off by the [ 2ndF ] [ . ].

Base Conversions:  Binary, Octal, and Hexadecimal modes are toggled by the key sequences [ 2ndF ] [ ÷ ], [ 2ndF ] [ × ], and [ 2ndF ] [ - ] respectively.  When going to these modes, the number in the displayed is converted.  Boolean functions  include NOT, AND, OR, XOR, XNOR, and NEG.

3-VLE Mode:  The 3-Variable mode solves 3 x 3 systems of linear equations:

a1 * x + b1 * y + c1 * z = d1
a2 * x + b2 * y + c2 * z = d2
a3 * x + b3 * y + c3 * z = d3

The mode solves for x, y, and z, and gives the determinant of the matrix

[ [ a1, b1, c1 ]
[ a2, b2, c2 ]
[ a3, b3, c3 ] ]

The 3-VLE mode becomes a stable for advanced Sharp scientific calculators during the late 1980s and 1990s. 

The mode is toggled on and off with the [ 2ndF ] [ +/- ] sequence.

Statistics Mode:  The EL-506A has one variable statistics.  There are three functions to transform data in normal distribution calculations.

→t:  Calculates (x - μ) / σ
→t Q(t):  Calculates the area between 0 to t
→t P(t): Calculates the area between -∞ to t

The statistics mode is toggled on and off with the [ 2ndF ] [ ON/C ].  I am not a fan of this key sequence, but thankfully it works because the calculator is not solar powered. 


The keyboard is a clean design.  Despite the small keys, the keys are responsive and easy to operate. 


The EL-506A is a nice vintage calculator with several advanced features like base conversions, the normal distribution functions, and 3 x 3 linear system solver. 


"Sharp EL-506A"
Retrieved December 19, 2019


All original content copyright, © 2011-2020.  Edward Shore.   Unauthorized use and/or unauthorized distribution for commercial purposes without express and written permission from the author is strictly prohibited.  This blog entry may be distributed for noncommercial purposes, provided that full credit is given to the author.


  1. Neat caclulator I probably overlooked. I used an EL-510S for about 20 years at work. Similar, but different. I may get the EL-506A since it has some functions I'd like to use. My 510S as well as many of my old caclulators is still going strong.
    Thanks for the post.

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