Interactive simulation
Drive an NPN into saturation and watch Q slide down the load line.
Raise the drive voltage and watch the Q point slide down the load line into saturation — the LED reaches full brightness right at that boundary.
What you can change
BJT base resistorA transistor used as a switch is not an amplifier — you deliberately throw its gain away. The mistake is dividing the load current by the datasheet hFE:…
Transmission lineA step launched into a mismatched trace, bouncing until it settles — why a short track suddenly matters.
UART frameOne byte on a wire that carries no clock — and the receiver's own timer walking off the bit centres.
Zener regulatorIt holds the voltage — until the load asks for more than it can spare.
555 astableThe capacitor sawtooth and output square of the classic astable.
ADC quantizationHow many bits before the staircase disappears into the sine?
ADC sampling & aliasingSample a sine too slowly and watch the alias ghost appear.
Battery dischargeLi-ion, LiFePO4, NiMH and alkaline curves under real load.
Bode plotGain against frequency on a log axis — where a filter actually stops working.