Sharp EL-8200 financial calculator questions

[robve]

The Sharp EL-8200 financial calculator from 1975 is a simple TVM and margin calculator.

   

What interested me in this calculator is the unusual key layout. It also has "TL", "Trend" and "n,x,x2" keys. Note that there are no EXP and LOG keys. As suspected, this calculator cannot solve for "n" or interest rate "i".

I could not find much information about this calculator online. Some things are easy to figure out. The ENT key enters a value into a register. The COMP key calculates. The COMP key also serves as a Shift key (aka F or 2ndF key). To recall (READ) a register, press ENT twice or COMP ENT will do.

But what about the "TL", "Trend" and "n,x,x2" keys? These apparently add data, because "n" increases by one and other registers are updated.

Does anyone on this forum own this machine with an instruction manual? I wonder what operations these "TL" and "Trend" keys perform?

- Rob

[AndiGer]

As I "unearthed" a Triumph-Adler 84F lately and wanted to know how to operate it I did some research and found the Qualitron 1439 / 2139 Financial Calculator Manual at Katie's website which has the same keys (and as I found the Silver-Reed SR-85 as well).

Your EL-8200 looks very similar. But I haven't found the "n,x,x2" key on neither the 84F nor the Qualitron.
But for your question concerning Trend/TL I think this manual would be of (some) help.

https://www.wass.net/manuals/Qualitron%202139.pdf

Andi

[robve]

(05-21-2023 02:08 PM)AndiGer Wrote:  As I "unearthed" a Triumph-Adler 84F lately and wanted to know how to operate it I did some research and found the Qualitron 1439 / 2139 Financial Calculator Manual at Katie's website which has the same keys (and as I found the Silver-Reed SR-85 as well).

Your EL-8200 looks very similar. But I haven't found the "n,x,x2" key on neither the 84F nor the Qualitron.
But for your question concerning Trend/TL I think this manual would be of (some) help.

https://www.wass.net/manuals/Qualitron%202139.pdf

Fantastic! The similarity is spot on! Thanks a lot for pointing in the right direction

The Sharp EL-8200 has exactly the same functions as the Qualitron 2139. I ran thought the manual and the examples. It is basically the same calculator. The only difference is that the Sharp's TAB and n,x,x² keys are labelled DS and ∑ on the Qualitron. The EL-8200 was introduced in 1975 and precedes the Qualitron 2139 by one year, according to https://www.calcuseum.com.

I found the answer to the TL and Trend functions. ENT Trend with COMP TL (trend line) give the intercept and slope of the trend line of a set of equidistant points, such as annual sales. It can also interpolate any given point with ENT n and COMP Trend.

Fortunately, and contrary to what I stated earlier, this calculator can in fact solve for "n" and interest "i". Even better, it supports amortization and can return the interest paid for a loan for a given period and annually (example shown on the last page of the manual).

I like this unusual financial calculator. It is quite capable with a few key presses, if you know how

- Rob