Spotlight: Sharp EL-520L

 Spotlight: Sharp EL-520L

Quick Facts

Model: EL-520L

Company: Sharp

Type: Solar Scientific Algebraic

Power: Solar with battery backup, 2 x LR 44

Case: Slide case

Memory: 7 memory registers: A, B, C, D, X, Y, M (M has memory addition and subtraction)

Years in Production: 1998

Display: 2 line, with results up to 10 digits

Shout out to Spaceboy Jeffy’s Vintage Emporium from where I purchased the calculator.

Scientific Calculations in Two Lines

The Sharp EL-520L is an early two-line scientific calculator. The top line is where mathematical expressions are entered, where the bottom line is where the results are displayed.

Expressions are entered as written, as noted by Sharp’s ADVANCED D.A.L. (Direct Algebraic Logic.

Example (degrees mode, float mode):

(top | bottom)

0.5; Screen: DEG | 0.5

×; Screen: DEG 0.5*_ |

e^; Screen: DEG 0.5*e^_ |

(sin 10°); Screen: DEG 0.5*e^(sin10) |

=; Screen: DEG 0.5*e^(sin10)= | 0.594818475

Modes

The modes of the EL-520L are controlled by the MODE keys and two toggle keys:

Toggle keys:

[ DRG ]: Change mode through the degrees, radians, and grads cycle. This is how the angle mode is changed on scientific calculators from the 1980s.

[ 2ndF ] [ DRG ] ( DRG> ): A variation of angle change. In this variation, a conversion of angle measurement.

[ 2ndF ] [ . ] (FSE): This the display format toggle: Floating point (no indicator), fixed point (FIX), scientific notation (SCI), engineering notation (ENG). The TAB function, accessed by [ 2ndF ] [ +/- ], set the number of decimal points in the fixed point, scientific notation, and engineering notation format.

There is also a modify (MDF) function that internally rounds the result to the fixed decimal point settings. The modify function does not affect anything stored to variables, however. I wish there was a round function (Round(n, decimal points)) instead, to be honest.

The Mode Key:

The [ MODE ] key offers three modes:

0: Normal. Normal calculator mode.

1: STAT x: Single variable statistics. The [ STO ] key becomes the comma key and memory plus key [ M+ ] becomes the data entry key.

2: STAT xy: Linear regression mode. The data is fit to the equation y = a + bx where a is the y-intercept and b is the slope.

In the statistic modes, the variables (A -D, X, Y, M) are not operable.

Replay and Editing Keys

In Normal mode, there are three editing functions:

[ DEL ]: The standard delete character.

[ 2^nd ] [ ← ] (⟲): Takes the cursor to the beginning of the last expression

[ 2^nd ] [ → ] ( ? ): Takes the cursor to the next number after the cursor’s position

There is no insert/replace mode. It seems like Sharp was experimenting with editing commands.

Order of Operations (Quirks?)

In a lot of algebraic calculators, the square function has higher priority than negation. Entering -4² returns -16.

Implied multiplication gets a higher priority than division and regular multiplication. Therefore if we enter the infamous expression:

6÷2(1+2) returns 1 instead of 9.

This is known as PEJMDAS where J is juxtaposition, or implied multiplication. For more information, please see The How and Why of Mathematics’ video from 2019:

https://www.youtube.com/watch?v=4x-BcYCiKCk

I’ll leave the debate at this point. Of course, when it doubt, use extra parenthesis or insert an additional multiplication sign ( × ).

One quirk: To insert variables (A, B, C, D, X, Y, M) into expressions, press [ 2ndF ] [ RCL ] (ALPHA).

Final Thoughts

The Sharp EL-520L is nice, basic level calculator with the ability to enter expressions. The EL-520L has a nice amount of the features that will satisfy most needs.

Source

Flow Simulation, Ltd. “Sharp EL-520 (ADVANCED D.A.L.)” calculator.org https://www.calculator.org/calculators/Sharp_EL-520L.html

Eddie

All original content copyright, © 2011-2026. 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.

Retro Review: Sharp EL-512 Scientific Calculator

Retro Review: Sharp EL-512 Scientific Calculator

Just The Facts:

Model:  EL-512

Company: Sharp

Type:  Keystroke Programmable 

Display:  10 digits, 8 digits with 2 digit exponents

Battery:  Battery: 2 x LR 44

Logic: AOS

Memory Registers: 10; 9 with an M registers.   

Programming Memory: 128 steps

Years:  1984-1987

Basic Information:  

https://www.calculator.org/calculators/Sharp_EL-512.html

The manual can be found here:

http://www.striegels.com/alan/sharp/Sharp%20EL-512%20Instruction%20Manual%20scanned.pdf

Features

* Trigonometric, Hyperbolic, Logarithmic, and Exponential Functions

* Constant Arithmetic 

* Automatic Multiplication  

* Convert to Hexadecimal Integers

* Convert to Degrees-Minutes-Seconds

* Linear Regression 

Constant Arithmetic

Pressing the equals key after a completed arithmetic operation will put the EL-512 into automatic arithmetic mode. This works only for addition, subtraction, and multiplication.  

Keystrokes	Interpretation	Examples
A [ + ] B [ = ] C [ = ] D [ = ]	A + B C + B D + B	150 [ + ] 80 [ = ] 230 76 [ = ] 156 52 [+/-] [ = ] 28
A [ - ] B [ = ] C [ = ] D [ = ]	A - B C - B D - B	150 [ - ] 80 [ = ] 70 76 [ = ] -4 52 [+/-] [ = ] -132
A [ × ] B [ = ] C [ = ] D [ = ]	A × B C × B D × B	20 [ × ] 4 [ = ] 80 5 [ = ] 100 0.25 [ = ] 5

Automatic Multiplication

Automatic (implied) multiplication occur in several areas:

The Famous A / BC Problem:

A [ ÷ ] B [ ( ] C [ ) ] [ = ]   returns A / (B * C)

Example:  9 [ ÷ ] 3 [ ( ] 2 [ ) ] [ = ]  returns 1.5

A [ ÷ ] B [ × ] C [ = ]   returns A / B * C

Example:  9 [ ÷ ] 3 [ × ] 2 [ = ] returns 6

.

Multiply by π:

A [ π ] returns A * π automatically.  

Example:  5 [ π ] returns 15.70796327

Implied Multiplication with Stored Numbers

With a stored number in a number register Kn:

A [ Kn ] returns A * Kn automatically

Example:  11.5 [ 2ndF ] (STO) 1;   5 [ Kn ] 1 returns 57.5

This is a very neat shortcut in keystroke programming.  

Convert to Hexadecimal Integers

The sequence [ 2ndF ] ( →HEX ) converts the number to hexadecimal form and changes the EL-512 to Hexadecimal mode.  Enter the digits A - F, by pressing [ 2ndF ] [ 0 ], [ 2ndF ] [ 1 ], etc.   I like the placement of A - F since A = 10, B = 11, etc.   Pressing the equals key returns the EL-512 to Decimal mode.

Unfortunately no Boolean functions are offered.

Linear Regression 

The memory keys act as data point entry.  In this mode, the multiplication key is used to indicate frequency.  The linear regression line is y = a + bx, where a is the intercept and b is the slope.

Programming

The programming model for the EL-512 is algebraic keystroke, which the manual refers to as Multiple Formula Reserve.  Programs are entered "blindly" so make sure that you have the program written down before entering it.  

You will also need to enter the program as a test case.  

The program space is 128 steps between 4 program spaces.  Every time a new program is entered, the old program in that slot is automatically cleared.  The LRN indicator shows that the EL-512 is in learn mode.  

[ x ]:  Asks the user to enter number.  Prompt numbers start with 1 and increases by 1.  This does not affect any storage registers.  Numbers entered after the [ x ] during program do not count as steps.   In run mode, enter the number, then press [ COMP ].  

[ 2ndF ] (LOOK):  This allows the program to temporarily stop to show the displayed value.  Continue the program in run mode by pressing [COMP].  

[ 1: ], [ 2: ], [ 2ndF ] ( 3: ), [ 2ndF ] ( 4: ):  In run mode, these keys and key sequences runs the program slot.  

There are no loops, integer, fraction, sign functions, or comparisons. Hence this model's programming is strictly for formulas only.  

Sharp EL-512 Program:  Rating Microphones in dBm

dBm = 10 log ( (E^2) / (0.001 * Z)) - 6

E:  voltage, prompt [ 1 ] 

Z:  resistance (ohms), prompt [ 2 ]

Program:

[ x ] 

(enter E)

x^2

÷

0.001

÷

[ x ] 

(enter Z)

=

log 

×

10

-

6 

=

Examples:

E = 40, Z = 80, Result:  37.01029996

E = 70, Z = 100, Result:  40.9019608

Source:

Davis, Don and Davis, Carolyn.  Sound System Engineering.  Howard W. Sams & Co. Inc:  Indianapolis.  1975  ISBN-10:  0-672-21156-4

Sharp EL-512 Program:  Heron's Formula

Area = √(S * (S - A) * (S - B) * (S - C)) where S = (A + B + C) / 2

A:  length of side A, prompt [ 1 ]

B:  length of side B, prompt [ 2 ]

C:  length of side C, prompt [ 3 ]

Program:

[ x ]

(enter A)

STO 1

+

[ x ] 

(enter B)

STO 2

+

[ x ] 

(enter C)

STO 3

=

÷

2

=

STO 4

×

( 

Kn 4

- 

Kn 1

)

×

(

Kn 4

-

Kn 2

) 

×

(

Kn 4

-

Kn 3

=

√

Examples:

A = 15.6, B = 13.8 , C = 14.8;  Area: 93.29390923

A = 48, B = 42, C = 57; Area:  986.9860371

Verdict

I think the most unique feature to the EL-512 is the implied multiplication.   I wish the programming functions had integer and fraction functions and even some comparisons.  The calculator is small and compact and fits very nicely in the wallet.   The keys, even though they are small to me, are nice and responsive.  

 

Eddie

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.