Non-graphing calcs and Electrical Engineering.

[Matt Agajanian]

Hi. From what I see with Electrical Engineering programs from keystroke program libraries for the SR-56, HP-25/33, TI-58, etc., I noticed complex numbers play a major role.

From what I’ve noticed and experienced, calcs like TI 36X Pro, 30X MathPrint, Casio 115/991 series have a quite limited complex number functionality.

Yeah, the short answer: use a programmable calculator or an upper-scale graphing calc (TI NSpire/NSpire CAS or II, 89 Titanium, Casio 9750GIII, Prizm, etc.).

Just to kick it around, are the 115/991, 36X/30X Pro of any use for any level of electrical or student engineering?

[KeithB]

Generally you only use complex numbers for "general purpose" analysis programs.
For everyday use, the standard reactance formulas "Xc = 1/2*pi*F*C" or reduced formulas like "1/2*pi*sqr(L*C)" for parallel resonance work just fine.

My HP41 worked fine with no complex support, and I rarely use complex numbers on my HP71 with MathPac.

After all, sliderules don't have a complex mode!

[Eddie W. Shore]

I echo Keith's statement.

I don't think there can be complex matrices on the fx-115/991 series.

[Matt Agajanian]

(10-12-2023 02:52 PM)Eddie W. Shore Wrote:  I echo Keith's statement.

I don't think there can be complex matrices on the fx-115/991 series.

Nope! I’ve worked the 115 & 991s for stuff not even in the manual. Complex matrix functionality is nowhere to be found. Eh. One less function menu. No biggie.

[Johnh]

Whether you need complex numbers on a calculator might depend on your particular circumstances, or if studying, any constraints for use in exams or in class.

I teach and practice engineering (structures) but also do a lot of electrical circuit analysis (hobby) using complex numbers to analyse large LRC circuits. I reckon that the need to do complex functions on a handheld device is very small. Once you learn the theory, which any calculator can support by simple arithmetic and geometry, then then next level, in practice, is best done using spreadsheets and then dedicated analysis software.

But a high-quality RPN calculator with nice positive buttons and some basic programming for quick ad-hoc tasks is still very nice, though I think most engineers just use a high-school Casio.

[Jlouis]

Grab the new HP15C coelector Edition , while it is still around.

Forget about TI.