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HP Forum Archive 15

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HP48g function
Message #1 Posted by Mark Davies on 20 Feb 2006, 1:21 p.m.

I am trying to figure out how to use my HP 48G to solve simultaneous equations using vectors for an electrical circuits. So far I am drawing a blank. It seems that all the schools are set up to use TIs' and no one knows the HPs'. Can anyone tell me how to use my HP to perform mesh analysis for AC circuits. I would be most greatful. Thank you.

Re: HP48g function
Message #2 Posted by Jan on 20 Feb 2006, 2:36 p.m.,
in response to message #1 by Mark Davies

I guess you calculate currents and voltages in complex notation by using (complex) amplitudes and impedances. The 48 can calculate with matrices in order to solve sets of linear equations (see the math menu and the manual on matrix calculations). I am not sure however if the 48 can handle complex matrices as well.

Re: HP48g function
Message #3 Posted by Karl Schneider on 20 Feb 2006, 2:36 p.m.,
in response to message #1 by Mark Davies

Mark --

You're in luck! In collecge 15 years ago, I not only solved AC and DC loop circuits using matrix functions on my HP-15C, but also now have a 48G at which I am reasonably competent.

After setting up the exactly-determined system-coefficient matrix and the system-measurement vector (both real-valued for DC systems; both complex-valued for AC systems):

  1. Choose "SOLVE" (above "7" key) with the green right-shift key
  2. Select "Solve lin systems"
  3. Enter the (square) matrix as A. Use brackets to enclose each row vector, with spaces between each coefficient; enclose all vectors within another set of brackets to make it a matrix. Enclose complex-valued numbers inside parentheses, with a comma between parts. Use the angle symbol if needed (green right-shift, "SPC"). Load the values with "ENTER".
  4. Enter the measurement-vector values as B, inside one set of brackets. (The same guidance applies for complex-valued numbers.) Load the values with "ENTER".
  5. Press the "SOLVE" soft-menu key ("F").
  6. The answers will be in X. Use "EDIT" (softmenu key "A") to see the full values.

I used this procedure successfully to solve two examples in the HP-15C manual.

BTW, this question could also have been posed in the Usenet group comp.sys.hp48, but it's not inappropriate here.


-- KS

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