There are a few scientific solar calculators on the market these days. Apart fom the TI-36X which is pretty popular, you'll find some from CASIO, in the fx-ES series for instance. We can mention the
fx-991ES PLUS-2 and the fx-85ES PLUS-2, for instance. They are current in CASIO's catalog. Dunno how easy they are to buy right now, though.
I second the suggestion. The Casios can keep up with fast typing as well. I have several fx-115MS which also support n,p,M,G, etc postfixes and can show the result with the postfix which makes it so much easier to use for electronics. Type 1/(2pi*10u*2.2k) to calculate the bandwidth of a simple RC filter using a 10uf capacitor and 2.2k Ohm resistor.
A current model with similar features seems to be the Casio fx-570MS-2
This inspired me to do something I’d been meaning to do for a while: attempt using units on the HP Prime. They’re a bit clumsy, but it does work, apparently!
As an example, I tried an op amp differentiatior homework problem, solving for the capacitor, giving me the equation C = 0.283/(2pi*500Hz*100kOhm)
Which gets entered as:
0.283/(2pi*500_(Hz)*100
E3_(Ohm))
(in textbook mode it’s displayed as a proper fraction, I’m just not bothering to do latex for the forum post)
It evaluates to:
900.8
E-12_(1/(Hz*Ohm))
Then you can run that result through the USIMPLIFY command:
USIMPLIFY(Ans)
Which returns
900.8
E-12_F
Pretty nifty.
You can also use SI prefixes, but they’ll carry through. (E.G. if you took 1mV and multiplied it by a million, it’ll output 1,000,000 mV, not 1000 V or 1 kV.)
The CONVERT command will do the conversions properly, for example 1m
3 to mm
3 will correctly output 1,000,000 mm
3, even though it doesn’t offer mm
3 as a unit to choose from the volume menu.
CONVERT(900.8
E-12_F,0_pF)
will output
900.8
E0_pF