Calculator

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KP2

Senior Member
Location
New Milford, CT
I need to buy a calculator for an engineering course. I was thinking about getting a TI 84 but I see some newer models. What do some of you guys recommend?
 

WastefulMiser

Senior Member
Location
ANSI World
Casio FX 115 -- you'll need it for the FE. Simple and easy to use.

Something better / more expensive? Mayhap a TI-89. Any professor that will not let you use it during an exam is probably is too lazy to make their tests "calculator-proof".
 

gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
100413-0655 EST

An RPN calculator. That is Reverse Polish Notation.

Generally this has meant HP. Before HP left the business I bought four 32SII to have some around for the future. This is a convenient small simple calculator useful for many applications. Normally I use a 48G or 12C.

HP re-entered the business, but I am not satisfied with what they have available. Hopefully my current supply will last for a while.

For many normal simple calculations RPN requires fewer key strokes, and I think more intuitive to use. If you are experienced in so called algebraic notation calculators, then you will find RPN difficult at first.

.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
100413-0655 EST

An RPN calculator. That is Reverse Polish Notation.

Generally this has meant HP. Before HP left the business I bought four 32SII to have some around for the future. This is a convenient small simple calculator useful for many applications. Normally I use a 48G or 12C.
Ancient history, I know, but my trusty HP 41CV with math card is what got me through engineering school back in the 80's. An RPN notation calculator was critical to AC circuit and signal courses because it could go back and forth between polar and rectangular coordinate notation internally (polar is necessary for multiplication and division of complex numbers, where rectangular is needed for addition and subtraction). Using a non-RPN calculator meant that in order to switch coordinate systems, you had to go outside the calculator, write things down, perform a coordinate conversion, and re-enter the numbers. It may be that "standard" notation calculator makers have found a way around this, but to this day I prefer RPN even for simple stuff. What is that "=" key for? :grin:

I got my first BS degree using a slide rule, but we won't go there...
 
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Hameedulla-Ekhlas

Senior Member
Location
AFG
I need to buy a calculator for an engineering course. I was thinking about getting a TI 84 but I see some newer models. What do some of you guys recommend?

If there is no prohibition for notebook laptop in course , my suggestion to you is to buy one notebook laptop and you can install any kind of math software you need.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
If there is no prohibition for notebook laptop in course , my suggestion to you is to buy one notebook laptop and you can install any kind of math software you need.
I don't know about that. A calculator will have dedicated and labeled keys that do certain things, where with a laptop running math software you'll have to use alphanumeric and function keys and remember what does what. Also, a calculator doesn't take up much desk space, and in an exam you'll have other things in front of you that you'll have to be dealing with. That's not to mention that with a calculator everything is there under one hand, and in an engineering exam setting you have to be FAST to survive. And I've never had to reboot my calculator.

Call me Old School (because I am), but I'd much prefer a hotrod calculator over a laptop for classroom use.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
I don't know about that. A calculator will have dedicated and labeled keys that do certain things, where with a laptop running math software you'll have to use alphanumeric and function keys and remember what does what. Also, a calculator doesn't take up much desk space, and in an exam you'll have other things in front of you that you'll have to be dealing with. That's not to mention that with a calculator everything is there under one hand, and in an engineering exam setting you have to be FAST to survive. And I've never had to reboot my calculator.

Call me Old School (because I am), but I'd much prefer a hotrod calculator over a laptop for classroom use.
Sorry to quote myself, but the edit function has gone away for some reason...

Anyway, I have been out of school for quite some time, but I would be surprised to hear that laptops are allowed in college exam situations. It seems to me that the potential for cheating would be too great, especially with the pervasiveness of wireless networking. Need an answer? Call (email) a friend.
 

StephenSDH

Senior Member
Location
Allentown, PA
I am a fan of the TI-89. But I bought it 5 years ago so they probably have newer and better. It is so much faster to just use a computer so it collects dust now.
 
An HP using RPN. It got me through many courses, and I also have troubles with that weird "=" key. Once you get used to it, it'll be much faster than the other kind.

(FWIW, I still know where my sliderule is... I also have a book around here they tells how to divide on an abacus. Never tried that, although I do have one.)
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
An HP using RPN. It got me through many courses, and I also have troubles with that weird "=" key. Once you get used to it, it'll be much faster than the other kind.

(FWIW, I still know where my sliderule is... I also have a book around here they tells how to divide on an abacus. Never tried that, although I do have one.)

I found that having had to use a slide rule for many years was a help even in the Calculator Age. With a slide rule, you get two or three significant digits but no decimal point; you have to keep track of orders of magnitude in your head. When a keystroke error on my calculator gave me a wrong answer, it was usually off in the weeds by orders of magnitude, and I was a bit quicker to catch it than some of my younger classmates who tended to more readily accept the calculator's answer.

Calculators started to come in near the end of my first college career. They were pretty big and to use one in class you had to claim a seat next to an outlet (the displays used a lot of power). If yours had a square root key, you were in high cotton.
 
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gar

Senior Member
Location
Ann Arbor, Michigan
Occupation
EE
100413-1211 EST

Why should calculators be allowed for in the normal classroom test? I suggest that for most purposes slide rules and pencil and paper should be adequate.

It is far more important that students learn fundamentals, rather than number crunching. For example, what happens to the speed of a permanent magnet DC motor when the armature voltage is reduce to 68%. No need for a calculator, do it in your head. What is the speed of a shunt wound DC motor if the shunt excitation current is reduced to 68%? Here I would use the slide rule.

What is the possible maximum phase shift of an RC network. No calculator required.

Why does a distorted sine wave look better when viewing the voltage across the capacitor in a series resistor capacitor network that is across the distorted source voltage? No calculator needed.

In a series RC circuit how do the capacitance and resistance relate to each other to produce a 45 degree phase shift at some frequency? No calculator needed.

What is the voltage on a capacitor that starts at 0 volts at time 0 and is fed from a DC voltage of V thru a switch and resistor at a time constant of 1, 2, 3, and 6? Do it again at the same times if the capacitor initial voltage is V/2? If the values are not already in your memory, probably not for all of these time periods, then a slide rule would be useful or a book of tables. The value for 6 is 0.997521247823 from my HP, From my K&E Log-Log I get 0.00245 and this subtracted from 1 is 0.99755 .

Having students use slide rules rather than calculators would provide better equality between students. Maybe fewer mistakes.

I believe that courses should be taught to get students to understand fundamental concepts, how to apply these, how to use common sense, and how to think. Because an answer comes from a calculator does not mean it is correct.

Some more on RPN. Suppose I have 5 items to add and then calculate sales tax and add that.

Key in first number, push Enter ..... this value is displayed as the bottom of the stack
Key in next number, push + ..... result is at bottom of stack
Etc.
Key in last of the 5 numbers, push + ..... result is at bottom of stack.
Push Enter ..... this puts the sum of the 5 numbers in two places on the stack
Key in the decimal equivalent of the tax rate, push x ..... this calculates tax and it is on the bottom of the stack
Push + ..... the result on the bottom of the stack is the total plus tax

.
 

Besoeker

Senior Member
Location
UK
100413-1211 EST

Why should calculators be allowed for in the normal classroom test? I suggest that for most purposes slide rules and pencil and paper should be adequate.
Because not all of us are Luddites?
;)
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
Because not all of us are Luddites?
;)
I take his point. The modern computing world is turning students into lightning fast number crunchers, but the fundamental underlying principles have not changed. Crunching more numbers does not necessarily yield a better understanding of the fundamentals; indeed, it may even serve to obscure them.
 

Hameedulla-Ekhlas

Senior Member
Location
AFG
Sorry to quote myself, but the edit function has gone away for some reason...

Anyway, I have been out of school for quite some time, but I would be surprised to hear that laptops are allowed in college exam situations. It seems to me that the potential for cheating would be too great, especially with the pervasiveness of wireless networking. Need an answer? Call (email) a friend.

He was insisting on advance and modern kind of calculator. Ofcourse, in exam laptop is not allowed. But for daily in class and home, it is better to have note-book laptop.
I am not insisting on this, it is only my suggestion.
 

ggunn

PE (Electrical), NABCEP certified
Location
Austin, TX, USA
Occupation
Electrical Engineer - Photovoltaic Systems
He was insisting on advance and modern kind of calculator. Ofcourse, in exam laptop is not allowed. But for daily in class and home, it is better to have note-book laptop.
I am not insisting on this, it is only my suggestion.
I would suggest otherwise. I would not advise a student to do all his homework with math software on computer and switch to a calculator for exams. That is, in my opinion, a recipe for disaster.
 

LarryFine

Master Electrician Electric Contractor Richmond VA
Location
Henrico County, VA
Occupation
Electrical Contractor
Is there anything these calculators do that one can't do with the Windows calculator in Scientific mode?
 
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