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Calculator recommendation?
tooki:
Take a look at HP’s current graphing calculator, the HP Prime. I think it meets every one of your requirements.
I have programmed a number of things into mine, eg. PAR3(x,y,z) to calculate 3 parallel resistors. Internally, that expands to 1/((1/x)+(1/y)+(1/z)), for example. (Except that you can enter and edit your custom functions with a full “textbook” entry with visual fractions, which this forum supports but I don’t know the syntax for... haven’t learned latex yet!)
You can download a full-featured HP Prime emulator for Mac and Windows for free, so you can try it out as much as you want before buying. It behaves exactly like the physical device. The emulator (and all the manuals, the computer connection software, etc) is on HP’s FTP server: ftp://ftp.hp.com/pub/calculators/Prime/ (connect as guest)
It’s not 100% perfect, but I love mine. It’s got a great keyboard, a glass touchscreen that’s actually useful, and it’s fast. It’s also very thin, which is nice.
VK3DRB:
Turn your telephone into a decent calculator...
RealCalc. Brilliant.
https://play.google.com/store/apps/details?id=uk.co.nickfines.RealCalc&hl=en_AU&gl=US
Prefer HP programmable?
https://play.google.com/store/apps/details?id=com.thomasokken.free42&hl=en_AU&gl=US
bd139:
--- Quote from: tooki on March 31, 2021, 04:06:50 pm ---Take a look at HP’s current graphing calculator, the HP Prime. I think it meets every one of your requirements.
I have programmed a number of things into mine, eg. PAR3(x,y,z) to calculate 3 parallel resistors. Internally, that expands to 1/((1/x)+(1/y)+(1/z)), for example. (Except that you can enter and edit your custom functions with a full “textbook” entry with visual fractions, which this forum supports but I don’t know the syntax for... haven’t learned latex yet!)
You can download a full-featured HP Prime emulator for Mac and Windows for free, so you can try it out as much as you want before buying. It behaves exactly like the physical device. The emulator (and all the manuals, the computer connection software, etc) is on HP’s FTP server: ftp://ftp.hp.com/pub/calculators/Prime/ (connect as guest)
It’s not 100% perfect, but I love mine. It’s got a great keyboard, a glass touchscreen that’s actually useful, and it’s fast. It’s also very thin, which is nice.
--- End quote ---
This is where the prime is inferior annoyingly. If you wanted 3 parallel resistors on the 48/50 you could write a simple program saved as RP
<< 1/X SWAP 1/X + 1/X >>
This could be applied to any number of resistors in parallel by using accumulation so say 4:
1000 2200 4700 8200 RP RP RP
So you build the program for two operands and then use the bottom of stack as the accumulator. A huge number of programs and functions can be turned into simple dual arity accumulator functions like that which the stack makes easy to handle.
I did write an APPLY function which would take all the stack values and apply a function N-1 times to it so you could just fill the stack up with resistors and then do:
‘RP’ APPLY
And it’d merrily chunk through them all.
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