PCF8574T IO Expansion Module – I2C Electronic Building Block

Expand your microcontroller's capabilities with the PCF8574T IO Expansion Module. This compact electronic building block uses the I2C communication protocol to add 8 extra general-purpose input/output (GPIO) pins to your Arduino, Raspberry Pi, or any compatible microcontroller — all over just two wires. Whether you're building a robotics project, a DIY automation circuit, or exploring electronics as a hobby, this module is a versatile and affordable addition to your toolkit.

Key Features

PCF8574T Chip: Industry-standard I/O expander IC with 8-bit quasi-bidirectional I/O port
I2C Interface: Communicates via standard I2C bus (SDA/SCL) — minimal wiring, maximum flexibility
Configurable Address: Three onboard address pins (A0, A1, A2) allow up to 8 modules on the same I2C bus
Wide Compatibility: Works seamlessly with Arduino, Raspberry Pi, ESP8266, ESP32, STM32, and more
Compact Design: Small PCB footprint makes it easy to integrate into breadboard or PCB builds
Operating Voltage: 2.5V – 6V, suitable for both 3.3V and 5V systems
Interrupt Output: Active-low interrupt signal notifies the host when an input changes state
Beginner-Friendly: Simple to wire and program — ideal for hobbyists and students alike

Specifications

IC: PCF8574T
Interface: I2C (2-wire)
I/O Pins: 8 (quasi-bidirectional)
Supply Voltage: 2.5V – 6V DC
I2C Address Range: 0x20 – 0x27 (configurable)
Max Current per Pin: 25mA sink / 1mA source
Package: Through-hole header pins for easy breadboard use

What Can You Build With It?

The PCF8574T IO Expansion Module is perfect for a wide range of DIY electronics projects:

Driving LED arrays or button matrices
Reading multiple sensor states simultaneously
Controlling relays or output devices
LCD display interfacing (commonly used for I2C LCD backpacks)
Home automation prototypes and learning kits

Great for Hobbyists & Learners

This electronic building block is a go-to component for STEM education, maker spaces, and electronics enthusiasts of all skill levels. Pair it with other modules to build increasingly complex and creative circuits.

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Frequently Asked Questions

Q: What is the PCF8574T IO Expansion Module used for?

A: The PCF8574T IO Expansion Module is used to expand the number of GPIO (General Purpose Input/Output) pins available on a microcontroller such as Arduino or Raspberry Pi. It communicates via the I2C bus, allowing you to control 8 additional digital I/O pins using only 2 wires (SDA and SCL).

Q: Is the PCF8574T IO Expansion Module compatible with Arduino?

A: Yes! This module is fully compatible with Arduino, Raspberry Pi, ESP8266, ESP32, STM32, and virtually any microcontroller that supports the I2C communication protocol. It is easy to wire and there are many open-source libraries available to get you started quickly.

Q: Can I use multiple PCF8574T modules on the same I2C bus?

A: Absolutely. The PCF8574T features three configurable address pins (A0, A1, A2) that allow you to set a unique I2C address for each module, enabling up to 8 individual modules to coexist on the same two-wire I2C bus — giving you up to 64 additional I/O pins!

Q: What voltage does the PCF8574T IO Expansion Module operate at?

A: The module operates at a supply voltage of 2.5V to 6V DC, making it compatible with both 3.3V systems (like Raspberry Pi and ESP32) and 5V systems (like most Arduino boards).

Production & Packaging Notice

To maintain high stock availability and fast shipping times, our items are sourced from multiple verified manufacturing facilities. While the core quality, materials, and product specifications remain identical, you may notice slight variations in the packaging design, manufacturing origin, or the wording of the printed instructions.