分析电路

求有两个电源和三个电阻电路的电流.

In[1]:=

g = \!$\*
GraphicsBox[
NamespaceBox["NetworkGraphics",
DynamicModuleBox[{Typeset`graph = HoldComplete[
Graph[{"\!\(\*SubscriptBox[\(J$, $1$]\)", 
          "\!$\*SubscriptBox[\(J$, $2$]\)", 
          "\!$\*SubscriptBox[\(J$, $3$]\)", 
          "\!$\*SubscriptBox[\(J$, $4$]\)"}, {{{1, 4}, {4, 2}, {4,
           3}, {2, 1}, {3, 1}}, Null}, {
         AspectRatio -> Full, 
          EdgeLabels -> {
           DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $4$]\)", 
              "\!$\*SubscriptBox[\(J$, $2$]\)"] -> Placed[
Labeled[
Graphics[
GeometricTransformation[
GeometricTransformation[{
AbsoluteThickness[1], 
Opacity[1], 
Dashing[{}], 
Line[{{-90., 0.}, {90., 0.}}], 
Rectangle[{-110, -10}, {-90, 10}], {
EdgeForm[{
Opacity[1], 
AbsoluteThickness[1], 
Dashing[{}]}], 
FaceForm[
RGBColor[1, 1, 1]], 
Rectangle[{90, -10}, {110, 10}], 
Rectangle[{-70, -30}, {70, 30}]}}, {{{0.1, 0}, {0, 0.1}}, {0, 0}}], {
                 0, 0}], ImageSize -> 65], 
Style["\!$\*SubscriptBox[\(R$, $2$]\)", 12], Top], {0.5, {
Rational[1, 2], 0.39}}], 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $4$]\)", 
              "\!$\*SubscriptBox[\(J$, $3$]\)"] -> Placed[
Labeled[
Graphics[
GeometricTransformation[
GeometricTransformation[{
AbsoluteThickness[1], 
Opacity[1], 
Dashing[{}], 
Line[{{-90., 0.}, {90., 0.}}], 
Rectangle[{-110, -10}, {-90, 10}], {
EdgeForm[{
Opacity[1], 
AbsoluteThickness[1], 
Dashing[{}]}], 
FaceForm[
RGBColor[1, 1, 1]], 
Rectangle[{90, -10}, {110, 10}], 
Rectangle[{-70, -30}, {70, 30}]}}, {{{0.1, 0}, {0, 0.1}}, {0, 0}}], {
                 0, 0}], ImageSize -> 65], 
Style["\!$\*SubscriptBox[\(R$, $3$]\)", 12], Top], {0.66, {
Rational[1, 2], 0.39}}], 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $1$]\)", 
              "\!$\*SubscriptBox[\(J$, $4$]\)"] -> Placed[
Labeled[
Graphics[
GeometricTransformation[
GeometricTransformation[{
AbsoluteThickness[1], 
Opacity[1], 
Dashing[{}], 
Line[{{-90., 0.}, {90., 0.}}], 
Rectangle[{-110, -10}, {-90, 10}], {
EdgeForm[{
Opacity[1], 
AbsoluteThickness[1], 
Dashing[{}]}], 
FaceForm[
RGBColor[1, 1, 1]], 
Rectangle[{90, -10}, {110, 10}], 
Rectangle[{-70, -30}, {70, 30}]}}, {{{0.1, 0}, {0, 0.1}}, {0, 0}}], {
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Style["\!$\*SubscriptBox[\(R$, $1$]\)", 12], Top], {0.6, {
Rational[1, 2], 0.38}}], 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $3$]\)", 
              "\!$\*SubscriptBox[\(J$, $1$]\)"] -> Placed[
Labeled[
Graphics[{{
GrayLevel[1], 
Rectangle[{0, -1}, {0.3, 1}]}, {
Thickness[0.3], 
Line[{{0, -0.5}, {0, 0.5}}]}, {
Thickness[0.5], 
Line[{{0.5, -1}, {0.5, 1}}]}}, ImageSize -> 8], 
Style["\!$\*SubscriptBox[\(V$, $2$]\)", 12], Top], {0.25, {
Rational[1, 2], 0.39}}], 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $2$]\)", 
              "\!$\*SubscriptBox[\(J$, $1$]\)"] -> Placed[
Labeled[
Graphics[{{
GrayLevel[1], 
Rectangle[{0, -1}, {0.3, 1}]}, {
Thickness[0.5], 
Line[{{0, -1}, {0, 1}}]}, {
Thickness[0.3], 
Line[{{0.5, -0.5}, {0.5, 0.5}}]}}, ImageSize -> 8], 
Style["\!$\*SubscriptBox[\(V$, $1$]\)", 12], Top], {0.5, {
Rational[1, 2], 0.39}}]}, EdgeLabelStyle -> {5}, 
          EdgeShapeFunction -> {
           DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $2$]\)", 
              "\!$\*SubscriptBox[\(J$, $1$]\)"] -> ({
Arrowheads[{{0.05, 0.85}}], 
Arrow[#]}& ), 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $3$]\)", 
              "\!$\*SubscriptBox[\(J$, $1$]\)"] -> ({
Arrowheads[{{0.05, 0.8}}], 
Arrow[{
Part[#, 1], {
Part[#, 2, 1], 
Part[#, 1, 2]}, 
Part[#, -1]}]}& ), 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $4$]\)", 
              "\!$\*SubscriptBox[\(J$, $3$]\)"] -> ({
Arrowheads[{{0.05, 0.2}}], 
Arrow[{
Part[#, 1], {
Part[#, 1, 1], 
Part[#, 2, 2]}, 
Part[#, -1]}]}& ), 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $1$]\)", 
              "\!$\*SubscriptBox[\(J$, $4$]\)"] -> ({
Arrowheads[{{0.05, 0.92}}], 
Arrow[{
Part[#, 1], {
Part[#, 1, 1], 1}, {
Part[#, -1, 1], 1}, 
Part[#, -1]}]}& ), 
            DirectedEdge[
             "\!$\*SubscriptBox[\(J$, $4$]\)", 
              "\!$\*SubscriptBox[\(J$, $2$]\)"] -> ({
Arrowheads[{{0.05, 0.2}}], 
Arrow[#]}& )}, EdgeStyle -> {
GrayLevel[0]}, EdgeWeight -> {-100, -200, -300, 3, -4}, 
          ImagePadding -> {{10, 15}, {10, 25}}, 
          ImageSize -> {236., 149.}, PerformanceGoal -> "Quality", 
          VertexCoordinates -> {{-1.5, 0}, {-0.5, 0}, {-0.5, -1}, {
            1.5, 0}}, VertexLabels -> {"Name"}, VertexStyle -> {
GrayLevel[0]}}]], Typeset`boxes, Typeset`boxes$s2d = 
       GraphicsGroupBox[{{
Arrowheads[0.028937842778793414`], 
Directive[
Opacity[0.7], 
Hue[0.6, 0.7, 0.5]], 
GrayLevel[0], {
TagBox[{
Arrowheads[{{0.05, 0.92}}], 
ArrowBox[{{-1.5, 0.}, {-1.5, 1}, {1.5, 1}, {1.5, 0.}}]}, 
            "DynamicName", BoxID -> "EdgeLabelID$1"], 
InsetBox[
FormBox[
StyleBox[
TemplateBox[{
GraphicsBox[
GeometricTransformationBox[
GeometricTransformationBox[{
AbsoluteThickness[1], 
Opacity[1], 
Dashing[{}], 
LineBox[{{-90., 0.}, {90., 0.}}], 
RectangleBox[{-110, -10}, {-90, 10}], {
EdgeForm[{
Opacity[1], 
AbsoluteThickness[1], 
Dashing[{}]}], 
FaceForm[
RGBColor[1, 1, 1]], 
RectangleBox[{90, -10}, {110, 10}], 
RectangleBox[{-70, -30}, {70, 30}]}}, {{{0.1, 0}, {0, 0.1}}, {0, 
                    0}}], {0, 0}], ImageSize -> 65], 
StyleBox["\"\\!\$\\*SubscriptBox[\\(R\$, \$1\$]\\)\"", 12, 
                 StripOnInput -> False]}, "Labeled", 
               DisplayFunction -> (FormBox[
GridBox[{{
ItemBox[#2, DefaultBaseStyle -> "LabeledLabel"]}, {
TagBox[
ItemBox[
PaneBox[
TagBox[#, "SkipImageSizeLevel"], Alignment -> {Center, Baseline}, 
                    BaselinePosition -> Baseline], 
                    DefaultBaseStyle -> "Labeled"], 
                    "SkipImageSizeLevel"]}}, 
                  GridBoxAlignment -> {
                   "Columns" -> {{Center}}, "Rows" -> {{Center}}}, 
                  AutoDelete -> False, 
                  GridBoxItemSize -> {
                   "Columns" -> {{Automatic}}, 
                    "Rows" -> {{Automatic}}}, 
                  BaselinePosition -> {2, 1}], TraditionalForm]& ), 
               InterpretationFunction -> (RowBox[{"Labeled", "[", 
RowBox[{#, ",", #2, ",", "Top"}], "]"}]& )], 5, 
              StripOnInput -> False], TraditionalForm], 
Offset[{0, 2}, 
DynamicLocation["EdgeLabelID$1", Automatic, 
Scaled[0.6]]], 
ImageScaled[{
Rational[1, 2], 0.38}], BaseStyle -> "Graphics"]}, {
TagBox[{
Arrowheads[{{0.05, 0.85}}], 
ArrowBox[{{-0.5, 0.}, {-1.5, 0.}}]}, "DynamicName", 
            BoxID -> "EdgeLabelID$2"], 
InsetBox[
FormBox[
StyleBox[
TemplateBox[{
GraphicsBox[{{
GrayLevel[1], 
RectangleBox[{0, -1}, {0.3, 1}]}, {
Thickness[0.5], 
LineBox[{{0, -1}, {0, 1}}]}, {
Thickness[0.3], 
LineBox[{{0.5, -0.5}, {0.5, 0.5}}]}}, ImageSize -> 8], 
StyleBox["\"\\!\$\\*SubscriptBox[\\(V\$, \$1\$]\\)\"", 12, 
                 StripOnInput -> False]}, "Labeled", 
               DisplayFunction -> (FormBox[
GridBox[{{
ItemBox[#2, DefaultBaseStyle -> "LabeledLabel"]}, {
TagBox[
ItemBox[
PaneBox[
TagBox[#, "SkipImageSizeLevel"], Alignment -> {Center, Baseline}, 
                    BaselinePosition -> Baseline], 
                    DefaultBaseStyle -> "Labeled"], 
                    "SkipImageSizeLevel"]}}, 
                  GridBoxAlignment -> {
                   "Columns" -> {{Center}}, "Rows" -> {{Center}}}, 
                  AutoDelete -> False, 
                  GridBoxItemSize -> {
                   "Columns" -> {{Automatic}}, 
                    "Rows" -> {{Automatic}}}, 
                  BaselinePosition -> {2, 1}], TraditionalForm]& ), 
               InterpretationFunction -> (RowBox[{"Labeled", "[", 
RowBox[{#, ",", #2, ",", "Top"}], "]"}]& )], 5, 
              StripOnInput -> False], TraditionalForm], 
Offset[{0, 2}, 
DynamicLocation["EdgeLabelID$2", Automatic, 
Scaled[0.5]]], 
ImageScaled[{
Rational[1, 2], 0.39}], BaseStyle -> "Graphics"]}, {
TagBox[{
Arrowheads[{{0.05, 0.8}}], 
ArrowBox[{{-0.5, -1.}, {-1.5, -1.}, {-1.5, 0.}}]}, "DynamicName", 
            BoxID -> "EdgeLabelID$3"], 
InsetBox[
FormBox[
StyleBox[
TemplateBox[{
GraphicsBox[{{
GrayLevel[1], 
RectangleBox[{0, -1}, {0.3, 1}]}, {
Thickness[0.3], 
LineBox[{{0, -0.5}, {0, 0.5}}]}, {
Thickness[0.5], 
LineBox[{{0.5, -1}, {0.5, 1}}]}}, ImageSize -> 8], 
StyleBox["\"\\!\$\\*SubscriptBox[\\(V\$, \$2\$]\\)\"", 12, 
                 StripOnInput -> False]}, "Labeled", 
               DisplayFunction -> (FormBox[
GridBox[{{
ItemBox[#2, DefaultBaseStyle -> "LabeledLabel"]}, {
TagBox[
ItemBox[
PaneBox[
TagBox[#, "SkipImageSizeLevel"], Alignment -> {Center, Baseline}, 
                    BaselinePosition -> Baseline], 
                    DefaultBaseStyle -> "Labeled"], 
                    "SkipImageSizeLevel"]}}, 
                  GridBoxAlignment -> {
                   "Columns" -> {{Center}}, "Rows" -> {{Center}}}, 
                  AutoDelete -> False, 
                  GridBoxItemSize -> {
                   "Columns" -> {{Automatic}}, 
                    "Rows" -> {{Automatic}}}, 
                  BaselinePosition -> {2, 1}], TraditionalForm]& ), 
               InterpretationFunction -> (RowBox[{"Labeled", "[", 
RowBox[{#, ",", #2, ",", "Top"}], "]"}]& )], 5, 
              StripOnInput -> False], TraditionalForm], 
Offset[{0, 2}, 
DynamicLocation["EdgeLabelID$3", Automatic, 
Scaled[0.25]]], 
ImageScaled[{
Rational[1, 2], 0.39}], BaseStyle -> "Graphics"]}, {
TagBox[{
Arrowheads[{{0.05, 0.2}}], 
ArrowBox[{{1.5, 0.}, {-0.5, 0.}}]}, "DynamicName", 
            BoxID -> "EdgeLabelID$4"], 
InsetBox[
FormBox[
StyleBox[
TemplateBox[{
GraphicsBox[
GeometricTransformationBox[
GeometricTransformationBox[{
AbsoluteThickness[1], 
Opacity[1], 
Dashing[{}], 
LineBox[{{-90., 0.}, {90., 0.}}], 
RectangleBox[{-110, -10}, {-90, 10}], {
EdgeForm[{
Opacity[1], 
AbsoluteThickness[1], 
Dashing[{}]}], 
FaceForm[
RGBColor[1, 1, 1]], 
RectangleBox[{90, -10}, {110, 10}], 
RectangleBox[{-70, -30}, {70, 30}]}}, {{{0.1, 0}, {0, 0.1}}, {0, 
                    0}}], {0, 0}], ImageSize -> 65], 
StyleBox["\"\\!\$\\*SubscriptBox[\\(R\$, \$2\$]\\)\"", 12, 
                 StripOnInput -> False]}, "Labeled", 
               DisplayFunction -> (FormBox[
GridBox[{{
ItemBox[#2, DefaultBaseStyle -> "LabeledLabel"]}, {
TagBox[
ItemBox[
PaneBox[
TagBox[#, "SkipImageSizeLevel"], Alignment -> {Center, Baseline}, 
                    BaselinePosition -> Baseline], 
                    DefaultBaseStyle -> "Labeled"], 
                    "SkipImageSizeLevel"]}}, 
                  GridBoxAlignment -> {
                   "Columns" -> {{Center}}, "Rows" -> {{Center}}}, 
                  AutoDelete -> False, 
                  GridBoxItemSize -> {
                   "Columns" -> {{Automatic}}, 
                    "Rows" -> {{Automatic}}}, 
                  BaselinePosition -> {2, 1}], TraditionalForm]& ), 
               InterpretationFunction -> (RowBox[{"Labeled", "[", 
RowBox[{#, ",", #2, ",", "Top"}], "]"}]& )], 5, 
              StripOnInput -> False], TraditionalForm], 
Offset[{0, 2}, 
DynamicLocation["EdgeLabelID$4", Automatic, 
Scaled[0.5]]], 
ImageScaled[{
Rational[1, 2], 0.39}], BaseStyle -> "Graphics"]}, {
TagBox[{
Arrowheads[{{0.05, 0.2}}], 
ArrowBox[{{1.5, 0.}, {1.5, -1.}, {-0.5, -1.}}]}, "DynamicName", 
            BoxID -> "EdgeLabelID$5"], 
InsetBox[
FormBox[
StyleBox[
TemplateBox[{
GraphicsBox[
GeometricTransformationBox[
GeometricTransformationBox[{
AbsoluteThickness[1], 
Opacity[1], 
Dashing[{}], 
LineBox[{{-90., 0.}, {90., 0.}}], 
RectangleBox[{-110, -10}, {-90, 10}], {
EdgeForm[{
Opacity[1], 
AbsoluteThickness[1], 
Dashing[{}]}], 
FaceForm[
RGBColor[1, 1, 1]], 
RectangleBox[{90, -10}, {110, 10}], 
RectangleBox[{-70, -30}, {70, 30}]}}, {{{0.1, 0}, {0, 0.1}}, {0, 
                    0}}], {0, 0}], ImageSize -> 65], 
StyleBox["\"\\!\$\\*SubscriptBox[\\(R\$, \$3\$]\\)\"", 12, 
                 StripOnInput -> False]}, "Labeled", 
               DisplayFunction -> (FormBox[
GridBox[{{
ItemBox[#2, DefaultBaseStyle -> "LabeledLabel"]}, {
TagBox[
ItemBox[
PaneBox[
TagBox[#, "SkipImageSizeLevel"], Alignment -> {Center, Baseline}, 
                    BaselinePosition -> Baseline], 
                    DefaultBaseStyle -> "Labeled"], 
                    "SkipImageSizeLevel"]}}, 
                  GridBoxAlignment -> {
                   "Columns" -> {{Center}}, "Rows" -> {{Center}}}, 
                  AutoDelete -> False, 
                  GridBoxItemSize -> {
                   "Columns" -> {{Automatic}}, 
                    "Rows" -> {{Automatic}}}, 
                  BaselinePosition -> {2, 1}], TraditionalForm]& ), 
               InterpretationFunction -> (RowBox[{"Labeled", "[", 
RowBox[{#, ",", #2, ",", "Top"}], "]"}]& )], 5, 
              StripOnInput -> False], TraditionalForm], 
Offset[{0, 2}, 
DynamicLocation["EdgeLabelID$5", Automatic, 
Scaled[0.66]]], 
ImageScaled[{
Rational[1, 2], 0.39}], BaseStyle -> "Graphics"]}}, {
Directive[
Hue[0.6, 0.2, 0.8], 
EdgeForm[
Directive[
GrayLevel[0], 
Opacity[0.7]]]], 
GrayLevel[0], 
TagBox[{
TagBox[
DiskBox[{-1.5, 0.}, 0.030239520958083826`], "DynamicName", 
             BoxID -> "VertexID$1"], 
InsetBox[
FormBox["\"\\!\$\\*SubscriptBox[\\(J\$, \$1\$]\\)\"", 
              TraditionalForm], 
Offset[{2, 2}, 
DynamicLocation["VertexID$1", Automatic, {Right, Top}]], 
ImageScaled[{0, 0}], BaseStyle -> "Graphics"]}, "DynamicName", 
           BoxID -> "VertexLabelID$1"], 
TagBox[{
TagBox[
DiskBox[{-0.5, 0.}, 0.030239520958083826`], "DynamicName", 
             BoxID -> "VertexID$2"], 
InsetBox[
FormBox["\"\\!\$\\*SubscriptBox[\\(J\$, \$2\$]\\)\"", 
              TraditionalForm], 
Offset[{2, 2}, 
DynamicLocation["VertexID$2", Automatic, {Right, Top}]], 
ImageScaled[{0, 0}], BaseStyle -> "Graphics"]}, "DynamicName", 
           BoxID -> "VertexLabelID$2"], 
TagBox[{
TagBox[
DiskBox[{-0.5, -1.}, 0.030239520958083826`], "DynamicName", 
             BoxID -> "VertexID$3"], 
InsetBox[
FormBox["\"\\!\$\\*SubscriptBox[\\(J\$, \$3\$]\\)\"", 
              TraditionalForm], 
Offset[{2, 2}, 
DynamicLocation["VertexID$3", Automatic, {Right, Top}]], 
ImageScaled[{0, 0}], BaseStyle -> "Graphics"]}, "DynamicName", 
           BoxID -> "VertexLabelID$3"], 
TagBox[{
TagBox[
DiskBox[{1.5, 0.}, 0.030239520958083826`], "DynamicName", 
             BoxID -> "VertexID$4"], 
InsetBox[
FormBox["\"\\!\$\\*SubscriptBox[\\(J\$, \$4\$]\\)\"", 
              TraditionalForm], 
Offset[{2, 2}, 
DynamicLocation["VertexID$4", Automatic, {Right, Top}]], 
ImageScaled[{0, 0}], BaseStyle -> "Graphics"]}, "DynamicName", 
           BoxID -> "VertexLabelID$4"]}}], $CellContext`flag}, 
TagBox[
DynamicBox[GraphComputation`NetworkGraphicsBox[
         3, Typeset`graph, Typeset`boxes, $CellContext`flag], {
         CachedValue :> Typeset`boxes, SingleEvaluation -> True, 
          SynchronousUpdating -> False, 
          TrackedSymbols :> {$CellContext`flag}},
ImageSizeCache->{{10.980693309010109`, 
          233.14020984366067`}, {-79.55937532285577, 
          76.7513936293538}}],
MouseAppearanceTag["NetworkGraphics"]],
AllowKernelInitialization->False,
UnsavedVariables:>{$CellContext`flag}]],
AspectRatio->Full,
DefaultBaseStyle->{
      "NetworkGraphics", 
       FrontEnd`GraphicsHighlightColor -> Hue[0.8, 1., 0.6]},
FrameTicks->None,
GridLinesStyle->Directive[
GrayLevel[0.5, 0.4]],
ImagePadding->{{10, 15}, {10, 25}},
ImageSize->{236., 149.}]\);

找出闭合电路.

In[2]:=