7432 (74LS32, 74HC32): the quad OR gate chip, live

The 7432 is a 14-pin chip with four independent 2-input OR gates: each output nY is 1 when either input, or both, is 1. The 74LS32 and 74HC32 share the 7400's pinout, with VCC on pin 14 and GND on pin 7. This live chip has all four gates.

OR gates combine conditions: an interrupt from any of several sources, a carry that comes from either of two terms (as in the full adder), or the terms of a sum-of-products expression after AND gates have formed them. In CMOS an OR gate is a NOR followed by an inverter, six transistors in two stages (the CMOS OR gate shows it). The 7432 has the same pin positions as the 7400 and the 7408. 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× OR: four independent 2-input OR gates, Y = A OR 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 74LS32; 2 V to 6 V for the 74HC32).
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 or 1B = 1: 1Y goes to 1. Only 0 and 0 give 0.

7432 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

OR truth table (each gate)

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

Pin numbers are for the DIP and SOIC packages (TI SN74HC32 datasheet, checked 2026-10-25). See also the OR truth table.

You can also read the full theory in the lesson on the OR 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 7432 quad OR gate chip in the lab →

Frequently asked

What is a 7432 chip?

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

What is the difference between the 74LS32 and the 74HC32?

Same gates and pinout. The 74LS32 is TTL for a 5 V supply; the 74HC32 is CMOS, works from 2 V to 6 V and uses less power.

How do I make a NOR gate from a 7432?

Follow an OR gate with an inverter, such as one gate of a 7404, or use a 7402, which has four NOR gates.

How do I make a 4-input OR gate?

Use three gates of a 7432: OR the inputs in pairs with two gates, then OR the two results with the third.