# AC nodal analysis with a HP 50g, help needed

## Main Question or Discussion Point

I've got a small issue at hand right now.

I need to solve simultaneous equations with unknowns in order to do mesh and nodal analysis problems. The issue is, i can't figure out how to enter the equations in to get an answer out. My previous calculator was a t183+, so i'm not that well acquainted with the 50g or HP calculators in general.

The set of equations i'm trying to solve is

V1(2.5∠-29.9)-V2(0.5∠0)=24∠0
V1(0.5∠0)-V2(0.539∠21.80)=4∠0

solving for V1 and V2.

I'm using RPN mode as mentioned in another thread i found, and for the ∠ symbol i'm using the alpha+Rshift+6 insertion.

So far i've tried entering the following without success.

['X(2.5∠-2.29)-Y(0.5∠0.)=(2.5∠-2.29)']
['X(0.5∠-2.29)-Y(0.539∠21.80)=(4.∠0.)']
{X Y}

I keep getting "invalid syntax" on the angle symbols when entering the equations, yet when entered as just (2.5∠-29.9) on the stack, they auto-convert to rectangular form.

I've also tried with the rectangular equivelents like so.

['X(2.5,-0.099)-Y(0.5,0.)=(2.5,0.099)'] ENTER
['X(0.499∠-1.99)-Y(0.5,0.2)=(4.,0.)'] ENTER
{X Y} ENTER

That enters in properly and displays on the stack, but when i use Rshift+NUM.SLV MSLV i get "Bad Argument Type"

Please let me know what i'm doing wrong, and feel free to ask for any other information or screenshots if needed.

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The Electrician
Gold Member
Don't use MSLV or other solvers to solve this type of problem; use the matrix arithmetic capability of the HP50.

Put on level 2 of the stack:

[[ 24 ]
[ 4 ]]

and on level 1(in polar and degrees mode); read the manual for info on how to enter matrices:

[[ (2.5∠-29.9) (0.5∠180) ]
[ (0.5∠0) (0.539∠-158.2) ]]

Then press the divide key and see (in polar and degrees mode):

[[ (10.089∠35.570) ]
[ (5.448∠66.182) ]]

or in rectangular and degrees mode:

[[ (8.207,5.869) ]
[ (2.200,4.984) ]]

On the HP50 you won't see the double square brackets I've used here for a matrix; it will look more like standard matrix notation.

Thanks! Didn't know that that was possible.