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XOR gate (four CMOS NAND gates)

Logic Gates from Components · free online experiment, runs in your browser with no install or sign-up.

Open this experiment in the circuit simulator

Objective

Build XOR from four NAND gates (16 transistors).

Procedure

Use the Controls tab (or the batteries' Properties) to set each input to 0 V or 5 V and press Start Simulation; turn Live on and drag an input slider to watch the output.

Theory

With m = NAND(A, B): Y = NAND(NAND(A, m), NAND(B, m)) = A ⊕ B. This is the classic four-NAND XOR: the output is 1 only when the inputs differ.

Questions to answer

Show that this circuit equals A·B' + A'·B.

Components used

8 × 2N7000 N-MOSFET, 8 × BS250 P-MOSFET, 3 × Battery / DC source, LED 5mm Red, Panel voltmeter, Resistor 220 ohm 1/4W

About the model

Ideal wires; component models as listed in the catalogue (no parasitics, no temperature drift). Built without a breadboard so the schematic stays readable.