Semiconductor & Electronics Lab

Everywhere

• Topic tabs (under the title) switch between simulations in this lab. Some topics have smaller buttons under the stage for their screens.
• Teach shows live equations with the current numbers and "What to notice" points. Practice gives a numeric problem and a quiz.
• Move the sliders or tap the chips in the right-hand panel. The readings box updates live.
• Pause / Restart control the animation. Clean view hides everything except the stage, for projecting or recording; press Esc to leave it.
• In Practice, type a number (e.g. 12.5 or 3.2e-10), press Check or Enter. Show it on the stage sets the simulation to that problem.
• Nothing is saved: scores reset when the page is reloaded.

Language

• Choose English or বাংলা once on the home page (top right); every lab then opens in that language — tabs, controls, readings, equations, notes, problems and quizzes.

Bands & doping

• Energy bands: conductor, semiconductor and insulator side by side; choose Si, Ge, GaAs or diamond and raise the temperature to see electrons cross the gap.
• Doping: the silicon lattice with a phosphorus atom (free electron) or a boron atom (hopping hole), and the donor/acceptor levels.
• Carriers & temperature: resistance against T for a metal and a semiconductor; n, p and n p = n_i² for the donor density you set.

p-n junction

• Depletion layer: watch it form — diffusion, recombination, fixed ions, the built-in field and V₀ (0.7 V Si, 0.3 V Ge).
• Forward & reverse bias: slide the applied voltage from −6 V to +1 V; the barrier, the layer width and the current change with it.
• I–V characteristic: the diode curve with the knee, the tiny reverse current and breakdown; static and dynamic resistance at the working point.

Rectifier

• Half-wave: the circuit with the diode switching on and off, input and output waveforms, V_dc = V_m/π.
• Full-wave: centre-tap (2 diodes) or bridge (4 diodes), which diodes conduct, V_dc = 2V_m/π, ripple at 2f, PIV.
• Capacitor filter: set C and R_L; the output charges to the peak and sags between peaks; ripple ≈ V_m/(2fRC).

Transistor

• Structure & action: n-p-n or p-n-p, the two bias batteries, carriers crossing the thin base, I_E = I_B + I_C, α and β.
• CE characteristics: I_C against V_CE for several I_B with the Q point, cut-off, saturation and active regions.
• CE amplifier: the circuit, input and inverted output waveforms, gain ≈ R_C/r_e, and clipping when the input is too large.

Logic gates

• The basic gates: AND, OR, NOT, NAND, NOR, XOR — click the inputs, watch the output lamp and the truth-table row.
• Universal NAND: NOT, AND and OR built from NAND gates, De Morgan, and a half adder.
• Binary numbers: slide a decimal number and see its 8 bits, place values, octal and hex, and the repeated-division method.

Full guide with teaching tips: User manual (also as a PDF).