7486 (74LS86, 74HC86): the quad XOR gate chip, live

The 7486 is a 14-pin chip with four independent 2-input XOR (exclusive OR) gates: each output nY is 1 when its two inputs differ. The 74LS86 and 74HC86 share the 7400's pinout, with VCC on pin 14 and GND on pin 7. This live chip has all four gates.

XOR is the gate of arithmetic and error checking. It is the sum bit of a half adder, it compares two bits (equal gives 0), a chain of them computes parity, and with one input used as a control it is a programmable inverter: Y = A when the control is 0 and NOT A when it is 1, which is how an adder-subtractor flips B to subtract. XOR feedback is also what drives an LFSR and a CRC. A CMOS XOR is bigger than a NAND: the one on the CMOS XOR page uses 12 transistors. The 7486 has the same pin positions as the 7400. All 256 combinations of the eight inputs are checked before the page is built.

Live circuit: click the inputs to toggle them and watch the outputs update. It runs the real simulator, right here on the page.

Open this circuit in the lab →

What you need

4× XOR: four independent 2-input XOR gates, Y = A XOR B, numbered 1 to 4 as on the datasheet

Step by step

Power the chip: VCC on pin 14 and GND on pin 7 (5 V for the 74LS86; 2 V to 6 V for the 74HC86).
Each gate has two inputs, nA and nB, and an output nY; find their pins in the pinout below.
Tie every unused input to VCC or GND: TI's 74HC datasheets say unused inputs must be terminated, because a floating CMOS input can drift and draw current.
Set 1A = 1 and 1B = 0: 1Y is 1. Make the inputs equal and 1Y drops to 0.

7486 pinout

Pin	Name	Pin	Name
1	1A	14	VCC
2	1B	13	4B
3	1Y	12	4A
4	2A	11	4Y
5	2B	10	3B
6	2Y	9	3A
7	GND	8	3Y

XOR truth table (each gate)

A	B	Y
0	0	0
0	1	1
1	0	1
1	1	0

Pin numbers are for the DIP and SOIC packages (TI SN74HC86 datasheet, checked 2026-10-25). See also the XOR truth table.

You can also read the full theory in the lesson on the XOR gate. Prefer to build it yourself from scratch? Open the digiwleea lab and place the gates on the canvas, or start from the logic gate simulator.

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Each of these is one step from a transistor to a working CPU. Build every gate from CMOS transistors and work all the way up in the free digiwleea lab, with the free theory reference alongside.

Open the 7486 quad XOR gate chip in the lab →

Frequently asked

What is a 7486 chip?

A 14-pin chip with four independent 2-input exclusive-OR gates. VCC is pin 14 and GND pin 7, with the same pinout as the 7400, 7408 and 7432.

What is a 7486 used for?

Adding (the sum bit of a half adder), comparing bits, computing parity, and as a controlled inverter: holding one input at 1 inverts the other, holding it at 0 passes it through.

How do I make an XNOR gate from a 7486?

Follow an XOR gate with an inverter (one gate of a 7404), or use another XOR gate of the chip with one input tied to 1, which inverts the first gate's output.

What is the difference between the 74LS86 and the 74HC86?

Same gates and pinout. The 74LS86 is TTL for a 5 V supply; the 74HC86 is CMOS, works from 2 V to 6 V and uses less power.