Source voltage rows make the ideal diode threshold explicit. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.
highlighted = computed this step
Below-threshold source energy rejects
Charge 2 coulombs through source voltage 2 volts supplies 4 joules against the 6 joule barrier. Accepted is 0.
Es=qVs=2⋅2=4J<Eb=6J,accepted=0
Equality is the threshold-conducting row
Charge 2 coulombs through source voltage 3 volts supplies 6 joules against the 6 joule barrier. Accepted is 1.
Es=qVs=2⋅3=6J=Eb=6J,accepted=1
Above-threshold source energy conducts
Charge 2 coulombs through source voltage 4 volts supplies 8 joules against the 6 joule barrier. Accepted is 1.