Exercise:
Erkläre wie ein Transistor funktioniert!

Solution:
center tikzpicture % Draw the PNP transistor draw nodepnp anchorE Q ; % Add labels nodeanchoreast at Q.E E; nodeanchornorth at Q.B B; nodeanchorwest at Q.C C; % Add a voltage source and connections optional example draw Q.C -- ++ nodeanchorsouth +V_cc; draw Q.B -- ++- nodeanchoreast Input; draw Q.E -- ++- nodeanchornorth Output; % Draw arrows for clarity optional example draw- Q.B ++-. -- Q.B; draw- Q.E ++-. -- Q.E; tikzpicture center center tikzpicturescale. % Draw the silicon layers of the PNP transistor % Emitter P fillred! rectangle . nodemidway Emitter P; % Base N fillblue! . rectangle nodemidway Base N; % Collector P fillred! rectangle . nodemidway Collector P; % Draw boundaries drawthick rectangle .; drawthick -- ; % Separate emitter from base drawthick . -- .; % Separate base from collector % Label doping materials nodeanchorwest at .. P-doped silicon High; nodeanchorwest at .. N-doped silicon Low; nodeanchorwest at .. P-doped silicon Moderate; % Add arrows to indicate flow of charge draw-thick .. -- .. nodemidwayright Holes; draw-thick .. -- .. nodemidwayright Electrons; % Add terminals nodedrawcirclefillblackscale.labelleft:Emitter at . ; nodedrawcirclefillblackscale.labelleft:Base at . ; nodedrawcirclefillblackscale.labelleft:Collector at . ; % External labels nodecenter at -. PNP Transistor Structure with Silicon Doping; tikzpicture center center tikzpicturescale. % Parameters defatomsize. % Size of atoms defelexsize. % Size of electrons % Draw the silicon lattice foreach x in foreach y in % Draw the silicon atom shadeball colorblue x y circle atomsize nodewhite Si; % Draw valence electrons around the atom fillred x+. y circle elexsize; % Right fillred x-. y circle elexsize; % Left fillred x y+. circle elexsize; % Top fillred x y-. circle elexsize; % Bottom % Add a title optional nodecenter at .-. Silicon Lattice with Valence Electrons per Atom; tikzpicture center center tikzpicturescale. % Parameters defatomsize. % Size of atoms defelexsize. % Size of electrons % Draw the silicon lattice with n-doping foreach x in foreach y in % Condition for n-doping: Replace some Si atoms with Phosphorus P ifnumx ifnumy % Draw Phosphorus dopant atom shadeball colorgreen x y circle atomsize nodewhite P; % Valence electrons for Phosphorus fillred x+. y circle elexsize; % Right fillred x-. y circle elexsize; % Left fillred x y+. circle elexsize; % Top fillred x y-. circle elexsize; % Bottom fillred x+. y+. circle elexsize; % Extra electron else % Draw silicon atom shadeball colorblue x y circle atomsize nodewhite Si; % Valence electrons for silicon fillred x+. y circle elexsize; % Right fillred x-. y circle elexsize; % Left fillred x y+. circle elexsize; % Top fillred x y-. circle elexsize; % Bottom fi fi % Add a title optional nodecenter at .-. Silicon Lattice with n-Doping Phosphorus; tikzpicture center center tikzpicturescale. % Parameters defatomsize. % Size of atoms defelexsize. % Size of electrons % Draw the silicon lattice with p-doping foreach x in foreach y in % Condition for p-doping: Replace some Si atoms with Boron B ifnumx ifnumy % Draw Boron dopant atom shadeball colorpurple x y circle atomsize nodewhite B; % Valence electrons for Boron fillred x+. y circle elexsize; % Right fillred x-. y circle elexsize; % Left fillred x y+. circle elexsize; % Top % No electron on the bottom indicating a hole % Draw a hole missing electron drawredthick x y-. circle elexsize; else % Draw silicon atom shadeball colorblue x y circle atomsize nodewhite Si; % Valence electrons for silicon fillred x+. y circle elexsize; % Right fillred x-. y circle elexsize; % Left fillred x y+. circle elexsize; % Top fillred x y-. circle elexsize; % Bottom fi fi % Add a title optional nodecenter at .-. Silicon Lattice with p-Doping Boron; tikzpicture center