diff --git a/Electrical/Board_003/simulation/mbus_master_101.png b/Electrical/Board_003/simulation/mbus_master_101.png
new file mode 100644
index 00000000..04f2e498
Binary files /dev/null and b/Electrical/Board_003/simulation/mbus_master_101.png differ
diff --git a/Electrical/Board_003/simulation/mbus_master_101.qucs-s.dpl b/Electrical/Board_003/simulation/mbus_master_101.qucs-s.dpl
new file mode 100644
index 00000000..e69de29b
diff --git a/Electrical/Board_003/simulation/mbus_master_101.qucs-s.sch b/Electrical/Board_003/simulation/mbus_master_101.qucs-s.sch
new file mode 100644
index 00000000..4c7643b7
--- /dev/null
+++ b/Electrical/Board_003/simulation/mbus_master_101.qucs-s.sch
@@ -0,0 +1,156 @@
+<Qucs Schematic 0.0.20>
+<Properties>
+  <View=-14,8,2000,1199,0.774686,0,4>
+  <Grid=10,10,1>
+  <DataSet=mbus_master_101.qucs-s.dat>
+  <DataDisplay=mbus_master_101.qucs-s.dpl>
+  <OpenDisplay=1>
+  <Script=mbus_master_101.qucs-s.m>
+  <RunScript=0>
+  <showFrame=0>
+  <FrameText0=Title>
+  <FrameText1=Drawn By:>
+  <FrameText2=Date:>
+  <FrameText3=Revision:>
+</Properties>
+<Symbol>
+  <.ID -20 -16 SUB>
+  <Line -20 20 40 0 #000080 2 1>
+  <Line 20 20 0 -40 #000080 2 1>
+  <Line -20 -20 40 0 #000080 2 1>
+  <Line -20 20 0 -40 #000080 2 1>
+</Symbol>
+<Components>
+  <Lib D1 1 520 140 -34 6 0 3 "Z-Diodes" 0 "1N5350B" 0>
+  <GND * 1 40 210 0 0 0 0>
+  <Vrect V2 1 40 640 18 -26 0 1 "5 V" 1 "1 ms" 1 "1 ms" 1 "1 ns" 0 "1 ns" 0 "0 ns" 0>
+  <IProbe Pr3 1 520 370 -41 -26 0 3>
+  <R R1 1 240 600 -26 15 0 0 "10k" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
+  <IProbe Pr1 1 380 560 -26 16 0 0>
+  <GND * 1 520 670 0 0 0 0>
+  <GND * 1 40 730 0 0 0 0>
+  <_BJT BC337AP_Q2 1 400 250 8 -26 0 0 "npn" 0 "3.94e-14" 0 "1" 0 "0.974" 0 "0.8" 0 "0.1" 0 "109.4" 0 "14.25" 0 "7.4e-15" 0 "1.3" 0 "3.16e-13" 0 "1.2" 0 "175" 0 "20.5" 0 "0" 0 "0" 0 "0.0539" 0 "0.1259" 0 "1.1" 0 "6.3e-11" 0 "0.75" 0 "0.33" 0 "1.58e-11" 0 "0.505" 0 "0.39" 0 "1" 0 "0" 0 "0.75" 0 "0" 0 "0.5" 0 "7.5e-10" 0 "0" 0 "0" 0 "0" 0 "8.5e-08" 0 "26.85" 0 "0" 0 "1" 0 "1" 0 "0" 0 "1" 0 "1" 0 "0" 0 "0" 0 "3" 0 "1.11" 0 "26.85" 0 "1" 0>
+  <R R4 1 230 170 15 -26 0 1 "10k" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
+  <R R5 1 400 160 15 -26 0 1 "10k" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
+  <Vdc V1 1 40 140 18 -26 0 1 "42 V" 1>
+  <IProbe Pr4 1 630 210 -41 -26 0 3>
+  <IProbe Pr2 1 120 490 16 -26 0 1>
+  <GND * 1 230 500 0 0 0 0>
+  <IProbe Pr5 1 230 440 -41 -26 0 3>
+  <_BJT BC337AP_Q1 1 230 340 8 -26 0 0 "npn" 0 "3.94e-14" 0 "1" 0 "0.974" 0 "0.8" 0 "0.1" 0 "109.4" 0 "14.25" 0 "7.4e-15" 0 "1.3" 0 "3.16e-13" 0 "1.2" 0 "175" 0 "20.5" 0 "0" 0 "0" 0 "0.0539" 0 "0.1259" 0 "1.1" 0 "6.3e-11" 0 "0.75" 0 "0.33" 0 "1.58e-11" 0 "0.505" 0 "0.39" 0 "1" 0 "0" 0 "0.75" 0 "0" 0 "0.5" 0 "7.5e-10" 0 "0" 0 "0" 0 "0" 0 "8.5e-08" 0 "26.85" 0 "0" 0 "1" 0 "1" 0 "0" 0 "1" 0 "1" 0 "0" 0 "0" 0 "3" 0 "1.11" 0 "26.85" 0 "1" 0>
+  <R R3 1 150 340 -26 -53 0 2 "10k" 1 "26.85" 0 "0.0" 0 "0.0" 0 "26.85" 0 "european" 0>
+  <VProbe Vdrop2 1 960 180 -16 28 0 3>
+  <GND * 1 830 680 0 0 0 0>
+  <Vdc V3 1 160 700 18 -26 0 1 "5 V" 1>
+  <GND * 1 160 790 0 0 0 0>
+  <_BJT BC337AP_Q3 1 520 600 8 -26 0 0 "npn" 0 "3.94e-14" 0 "1" 0 "0.974" 0 "0.8" 0 "0.1" 0 "109.4" 0 "14.25" 0 "7.4e-15" 0 "1.3" 0 "3.16e-13" 0 "1.2" 0 "175" 0 "20.5" 0 "0" 0 "0" 0 "0.0539" 0 "0.1259" 0 "1.1" 0 "6.3e-11" 0 "0.75" 0 "0.33" 0 "1.58e-11" 0 "0.505" 0 "0.39" 0 "1" 0 "0" 0 "0.75" 0 "0" 0 "0.5" 0 "7.5e-10" 0 "0" 0 "0" 0 "0" 0 "8.5e-08" 0 "26.85" 0 "0" 0 "1" 0 "1" 0 "0" 0 "1" 0 "1" 0 "0" 0 "0" 0 "3" 0 "1.11" 0 "26.85" 0 "1" 0>
+  <_BJT BD136_138_140_Q4 1 830 320 8 -26 1 0 "pnp" 0 "2.9537e-13" 0 "1" 0 "1.021" 0 "1.0993" 0 "0.1" 0 "137" 0 "8.41" 0 "1.8002e-13" 0 "1.5" 0 "7.0433e-12" 0 "1.38" 0 "201.4" 0 "23.765" 0 "0.01" 0 "0.011" 0 "0.01" 0 "0.1109" 0 "1.98" 0 "2.1982e-10" 0 "0.7211" 0 "0.3685" 0 "6.8291e-11" 0 "0.5499" 0 "0.3668" 0 "0.5287" 0 "0" 0 "0.75" 0 "0" 0 "0.5" 0 "0" 0 "0" 0 "0" 0 "0" 0 "0" 0 "26.85" 0 "0" 0 "1" 0 "1" 0 "0" 0 "1" 0 "1" 0 "0" 0 "1.4883" 0 "3" 0 "1.2343" 0 "26.85" 0 "1" 0>
+  <IProbe Pr6 1 830 440 16 -26 1 3>
+  <_BJT BC337AP_Q5 1 1040 510 8 -26 0 0 "npn" 0 "3.94e-14" 0 "1" 0 "0.974" 0 "0.8" 0 "0.1" 0 "109.4" 0 "14.25" 0 "7.4e-15" 0 "1.3" 0 "3.16e-13" 0 "1.2" 0 "175" 0 "20.5" 0 "0" 0 "0" 0 "0.0539" 0 "0.1259" 0 "1.1" 0 "6.3e-11" 0 "0.75" 0 "0.33" 0 "1.58e-11" 0 "0.505" 0 "0.39" 0 "1" 0 "0" 0 "0.75" 0 "0" 0 "0.5" 0 "7.5e-10" 0 "0" 0 "0" 0 "0" 0 "8.5e-08" 0 "26.85" 0 "0" 0 "1" 0 "1" 0 "0" 0 "1" 0 "1" 0 "0" 0 "0" 0 "3" 0 "1.11" 0 "26.85" 0 "1" 0>
+  <.DC DC1 1 1600 370 0 38 0 0 "26.85" 0 "0.001" 0 "1 pA" 0 "1 uV" 0 "no" 0 "150" 0 "no" 0 "none" 0 "CroutLU" 0>
+  <R_SPICE R9 1 1330 430 -26 -53 0 2 "1k" 1 "" 0 "" 0 "" 0 "" 0>
+  <GND * 1 1240 700 0 0 0 0>
+  <GND * 1 1040 700 0 0 0 0>
+  <GND * 1 1450 700 0 0 0 0>
+  <R_SPICE R10 1 1450 510 -71 -26 0 3 "100k" 1 "" 0 "" 0 "" 0 "" 0>
+  <IProbe Pr9 1 1450 620 16 -26 1 3>
+  <IProbe Pr8 1 1240 620 16 -26 1 3>
+  <IProbe Pr7 1 1040 620 16 -26 1 3>
+  <R_SPICE R8 1 1240 330 15 -26 0 1 "10k" 1 "" 0 "" 0 "" 0 "" 0>
+  <Lib D2 1 1240 500 13 6 1 3 "Z-Diodes" 0 "1N750" 0>
+  <IProbe Pr10 1 1240 220 16 -26 1 3>
+  <R_SPICE R7 1 830 560 15 -26 0 1 "82" 1 "" 0 "" 0 "" 0 "" 0>
+  <R_SPICE R6 1 830 170 15 -26 0 1 "220k" 1 "" 0 "" 0 "" 0 "" 0>
+  <Idc I1 1 730 220 18 -26 1 3 "11 mA" 1>
+  <.SW SW1 1 1490 120 0 61 0 0 "DC1" 1 "lin" 1 "I1" 1 "6m" 1 "11m" 1 "21" 1 "false" 0>
+  <.SW SW2 1 1650 120 0 61 0 0 "SW1" 1 "lin" 1 "V1" 1 "21" 1 "42" 1 "22" 1 "false" 0>
+  <R_SPICE R2 1 520 510 15 -26 0 1 "8.2k" 1 "" 0 "" 0 "" 0 "" 0>
+</Components>
+<Wires>
+  <40 110 230 110 "" 0 0 0 "">
+  <40 170 40 210 "" 0 0 0 "">
+  <400 110 520 110 "" 0 0 0 "">
+  <400 110 400 130 "" 0 0 0 "">
+  <230 110 400 110 "" 0 0 0 "">
+  <230 110 230 140 "" 0 0 0 "">
+  <230 200 230 250 "" 0 0 0 "">
+  <400 190 400 220 "" 0 0 0 "">
+  <400 280 520 280 "" 0 0 0 "">
+  <40 600 40 610 "" 0 0 0 "">
+  <40 600 120 600 "TxD" 50 560 47 "">
+  <120 600 160 600 "" 0 0 0 "">
+  <520 280 520 320 "" 0 0 0 "">
+  <410 600 490 600 "" 0 0 0 "">
+  <410 560 410 600 "" 0 0 0 "">
+  <270 600 350 600 "" 0 0 0 "">
+  <350 560 350 600 "" 0 0 0 "">
+  <520 630 520 670 "" 0 0 0 "">
+  <520 240 520 280 "" 0 0 0 "">
+  <520 240 630 240 "" 0 0 0 "">
+  <520 170 630 170 "" 0 0 0 "">
+  <630 170 630 180 "" 0 0 0 "">
+  <520 400 520 480 "" 0 0 0 "">
+  <520 540 520 570 "" 0 0 0 "">
+  <120 520 120 600 "" 0 0 0 "">
+  <230 470 230 500 "" 0 0 0 "">
+  <230 370 230 410 "" 0 0 0 "">
+  <230 250 230 310 "" 0 0 0 "">
+  <230 250 370 250 "" 0 0 0 "">
+  <120 340 120 460 "" 0 0 0 "">
+  <180 340 200 340 "" 0 0 0 "">
+  <830 110 830 130 "mbusplus" 870 90 10 "">
+  <940 130 940 170 "" 0 0 0 "">
+  <830 130 940 130 "" 0 0 0 "">
+  <940 190 940 210 "" 0 0 0 "">
+  <830 210 940 210 "" 0 0 0 "">
+  <830 130 830 140 "" 0 0 0 "">
+  <830 200 830 210 "" 0 0 0 "">
+  <520 110 730 110 "" 0 0 0 "">
+  <830 210 830 290 "mbusminus" 870 260 14 "">
+  <520 320 520 340 "" 0 0 0 "">
+  <520 320 800 320 "pnpbase" 690 340 252 "">
+  <160 600 210 600 "" 0 0 0 "">
+  <160 600 160 670 "" 0 0 0 "">
+  <160 730 160 790 "" 0 0 0 "">
+  <830 350 830 380 "" 0 0 0 "">
+  <830 470 830 510 "" 0 0 0 "">
+  <830 590 830 680 "" 0 0 0 "">
+  <830 510 830 530 "" 0 0 0 "">
+  <830 510 1010 510 "q5base" 960 440 83 "">
+  <1240 360 1240 430 "" 0 0 0 "">
+  <1040 430 1040 480 "" 0 0 0 "">
+  <1040 430 1240 430 "" 0 0 0 "">
+  <1240 430 1300 430 "" 0 0 0 "">
+  <1240 430 1240 470 "" 0 0 0 "">
+  <1360 430 1450 430 "RxD" 1430 400 39 "">
+  <1450 430 1450 480 "" 0 0 0 "">
+  <1040 540 1040 590 "" 0 0 0 "">
+  <1450 540 1450 590 "" 0 0 0 "">
+  <1450 650 1450 700 "" 0 0 0 "">
+  <1240 650 1240 700 "" 0 0 0 "">
+  <1040 650 1040 700 "" 0 0 0 "">
+  <1240 530 1240 590 "" 0 0 0 "">
+  <830 110 1240 110 "" 0 0 0 "">
+  <1240 110 1240 190 "" 0 0 0 "">
+  <1240 250 1240 300 "" 0 0 0 "">
+  <730 110 830 110 "" 0 0 0 "">
+  <730 110 730 190 "" 0 0 0 "">
+  <730 250 730 380 "" 0 0 0 "">
+  <830 380 830 410 "" 0 0 0 "">
+  <730 380 830 380 "" 0 0 0 "">
+</Wires>
+<Diagrams>
+  <Rect 82 1100 487 230 3 #c0c0c0 1 00 1 0 50000 250000 1 -0.0722351 0.5 0.842553 1 -1 1 1 315 0 225 "" "" "">
+	<"ngspice/mbus_master_101:v(q5base)" #0000ff 0 3 0 0 0>
+  </Rect>
+  <Rect 670 1103 560 223 3 #c0c0c0 1 00 1 0 20000 249006 1 -0.00234274 0.01 0.0263551 1 -1 0.5 1 315 0 225 "" "" "">
+	<"ngspice/mbus_master_101:i(pr6)" #0000ff 0 3 0 0 0>
+  </Rect>
+  <Rect 1330 1112 512 232 3 #c0c0c0 1 00 1 -1 0.2 1 1 -1 0.5 1 1 -1 0.5 1 315 0 225 "" "" "">
+	<"ngspice/mbus_master_101:v(rxd)" #0000ff 0 3 0 0 0>
+  </Rect>
+</Diagrams>
+<Paintings>
+  <Text 1470 500 12 #000000 0 "Arduino input pin">
+  <Text 1290 810 12 #000000 0 "RxD swicthes polarity at around 8mA through R7 regardless of the supply voltage.">
+</Paintings>