This simulator is a digital trainer for the six basic gates. You set the inputs, pick the gate and watch the signal travel through a gate symbol to an output lamp, then compare the result with the complete truth table, either by hand or by letting the lab cycle through the rows.
• A 3D trainer with input switches, the selected gate symbol, digital signal paths, an output indicator and a truth-table display. • A Gate selector (AND, OR, XOR, NAND, NOR, NOT), manual inputs A and B, and an Automatically cycle truth-table rows checkbox. • Readouts for active A, active B, gate output, the active truth-table row and how many of the four rows give a high output. • Restart demonstration and Advance event buttons, plus experiments for XOR with equal inputs and for NOT ignoring B.
AND is high only when both inputs are high; OR is high when either is; XOR is high only when the inputs differ. NAND is the inversion of AND, NOR the inversion of OR, and NOT simply inverts A. Comparing the counts of high outputs across the four rows makes the pairs obvious: AND has one, OR three, XOR two, NAND three and NOR one. NOT is deliberately shown as a one-input gate, so input B has no effect on it — the output is one whenever A is zero.
These are ideal combinational gates in Boolean logic. Real devices also have voltage thresholds, propagation delays, fan-out limits and hazards, all outside this model. Each event lasts 0.8 animation seconds, and the signal markers are explanatory rather than measured hardware timing.
XOR. OR is also high for inputs of 1 and 1, which is the difference the XOR experiment highlights: with equal inputs, XOR outputs zero.
One. Input B is deliberately ignored, so the output is the inverse of A regardless of B.
NAND is the complement of AND: it outputs zero only when both inputs are one. Likewise NOR is the complement of OR.
It steps through the four A and B combinations automatically so you can see the output for each row without changing the switches yourself, and the active-row readout tells you which row is shown.