# 7400 Series Guide: 74HC132/74LS132 (NAND gates)

The 74×132 (ex 74HC132) is a chip with four basic NAND gates that have Schmitt triggers on the inputs to the gates. This type of input makes it more robust against noise, but also makes it easy to build simple oscillators!

## What does the 74HC132 / 74LS132 do?

The 74×132 gives you four NAND gates with Schmitt triggers. A NAND gate is a logic gate that outputs 0 (LOW) only if all of its inputs are 1 (HIGH). In the truth table below, you can see what the output will be for any given input:

## What is a Schmitt Trigger?

So, here’s the thing. The gate inputs being Schmitt-triggered basically means that the threshold for a 0 becoming a 1 is not the same as for a 1 becoming a 0.

Think of it like this. Say, you’re running this chip on three AA batteries, which gives you 4.5V. For the input to be read as a 1, or HIGH, the voltage has to climb over 2V. But, when you’re already at HIGH, the voltage needs to dip under 0.9V for the input to be recognized as a 0, or LOW. You can get these numbers from the datasheet, by the way.

## How To Use This Chip

The 74HC132 comes in a 14-pin package, and you need to connect it to power before you can use it. Most 7400 ICs support a VCC voltage of 5V. One difference between the HC and LS version of the chip is that the 74HC132 supports 2V to 6V, while the 74LS132 only supports 5V.

Once you’ve connected the chip to a power supply, you can use any of the four NAND gates inside. The amount of current you can pull out depends on the chip you have:

74HC132:
Each gate output of the 74HC132 can sink or source around 4mA when you power it with 5V.

74LS132:
HIGH-Level Output Current: 0.4 mA
LOW-Level Output Current: 8 mA (some chips support 16 mA)

## 74HC132 Circuit Example: Mini-Synthesizer

Here’s a simple project you can build with the NAND gates in the 74HC132 IC. This will only work with Schmitt-triggered NAND gates, so you need the 74×132 or similar chip. Each NAND gate creates a different frequency. When you combine them, it sounds like something out of an old computer.

To build this circuit, you’ll need the following parts:

• 1 x 74HC132
• 1 x Buzzer
• 2 x 10 kΩ potentiometers (RV1, RV2)
• 2 x 100 kΩ potentiometers (RV3, RV4)
• 1 x 10 µF Capacitor (C1)
• 1 x 2.2 µF Capacitor (C2)
• 1 x 0.1 µF Capacitor (C3)
• 1 x 10 nF Capacitor (C4)

## Alternatives and Equivalents for 74HC132 / 74LS132

There are many versions of the 74×132 chip. They all have the same functionality and pinout but with different specifications such as supported voltages and maximum current output.

Here’s a list of a few equivalents of this chip:

• 74HC132 (High-speed CMOS)
• 74HCT132 (High-speed CMOS, TTL compatible)
• 74LS132 (High-speed TTL)
• 74LVC132 (Low Voltage TTL)
• 74ALS132 (Advanced Low-Power Schottky TTL)
• 74F132 (Very High Speed)
• 74C132 (CMOS, similar to the 4000-series)

Some manufacturers also add a prefix, such as the SN74HC132 and SN74LS132 by Texas Instruments.

Can’t find the 74×132 anywhere? Then try one of the following IC alternatives:

• CD4093 – Quad 2-input NAND gates (Schmitt-trigger).

If you can’t find the 74×132 IC in your local electronics store, don’t worry, you’ll most likely find it in one of the stores listed on this page of online stores where you’ll find components and tools for all your electronics projects.