**Retro Review: Sharp EL-5100**

Company: Sharp

Year Introduced: 1979

Type: Scientific, Formula Programming

Memory: 80

Operating System: Algebraic

Memory Registers: 11, A through J, M

Background

I have to give a shout out to the Pasadena Antique Mall in Pasadena, California. The EL-5100 was a lucky find for me, and the ladies at the counter were kind enough to let me walk quickly to nearby Target to get batteries so the EL-5100 can be tested. The calculator tested perfectly! If you are in the greater Los Angeles area, the Pasadena Antique Mall is great place to visit for all things retro.

**Landscape and Thin Calculator**

The EL-5100 is a light weight calculator in a silver, thin design. The calculator is well built and the keys are solid. The keys are arranged in three sections, from left to right:

* Scientific functions

* Number keypad and arithmetic functions

* Storage and alpha keys: A-J, M

A staple of calculators from the 1970s is the physical mode switch. The EL-5100 has one mode switch:

* AER: Program and store formulas

* COMP: Computational mode

* STAT: Statistics mode, including linear regression (y = a + bx)

**Formula Storage**

The EL-5100 can store up to five formula areas, with 80 steps allocated between them. The formulas can be separate or stored as a chain of formulas. An example of the chain formula:

c = √(a^2 + b^2)

d = c / (b + c)

would be stored as:

(switch to AER mode, CA)

1; f(A,B)=√(A^2+B^2) STO C ◣

2; C ÷ (B + C) STO D

(switch back to COMP)

Press [ COMP ]

(an example)

A =? (pressing COMP again takes the last value of A)

Example: Let A = 19, B = 79

[COMP]

A = ? 19 [COMP]

B = ? 79 [COMP]

1; ANS 1 = 81.25269226 (C)

[2nd F] 2;

2; ANS 1 = 0.507028563 (D)

An alternative way to chain formulas (multistep):

1; f(A,B)=√(A^2+B^2) STO C, C ÷ (B + C) STO D

Example: Let A = 19, B = 79

[COMP]

A = ? 19 [COMP]

B = ? 79 [COMP]

1; ANS 1 = 81.25269226 (C) [COMP]

2; ANS 2 = 0.507028563 (D)

You can store immediate results, however, they will end the execution. However, this is still handy when you are using the M register and the M+ feature.

* Note: In AER mode, the [ COMP ] key is the comma.

**Statistics Mode**

In STAT mode, it was common for Sharp calculators to assign data entry keys to the M register keys.

[ RM ] becomes CD (clear data)

[ →M ] becomes the comma for bivariate data (x,y)

[ M+ ] becomes DATA for storing data

The multiplication key can be used to store data with frequency greater than. However, you can do mathematical operations as long as they are enclosed in parenthesis.

Even though the variable keys A-J are not available during STAT mode, the stat values are stored in the following variables and can be used later in COMP mode.

E = n

F = ∑x

G = ∑x^2

H = ∑xy

I = ∑y

J = ∑y^2

**Sharp EL-5100 vs TI-68**

The EL-5100 ushered in a category of formula storage calculators. Here is a comparison table between 1979's EL-5100 and 1989's TI-68.

EL-5100 | TI-68 | |
---|---|---|

1979 | Year of Introduction | 1989 |

3 x SR44/LR44/357 | Batteries | 1 x CR2032 |

landscape | Form | portrait |

5, sequential | Number of Storage Areas | 1 at a time, as memory allows |

80 | Number of Steps | 440 (55 registers) |

y = a + bx, r | Linear Regression | y = SLP x + ITC, COR |

A through J, M | Variable Names | variable names up to 3 characters |

chain formulas, physical mode switch | Unique Features | complex numbers, base conversions, integrals, solver, conversions |

**Verdict**

The EL-5100 is a simple calculator which is a joy to use.

Eddie

All original content copyright, © 2011-2021. 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.

Used that in the Marines to calculate microwave shots.

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