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:
The manual can be found here:
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
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