Description

The ULN2803A is a highly popular 8-channel Darlington transistor array designed to interface low-current logic systems (Arduino, ESP32, Raspberry Pi) with higher current/voltage loads. Each of its eight channels contains a Darlington pair capable of sinking up to 500mA per channel, making it ideal for relay boards, LED strips, stepper motors, and solenoid control.

The chip features integrated flyback diodes, allowing safe operation with inductive loads such as relays and motors without needing additional protection components. The ULN2803A accepts both 3.3V and 5V logic, making it widely compatible across microcontroller platforms.

Common applications include relay driving circuits, stepper motor control, LED displays, home automation, robotics, vending machines, and industrial automation.

Key Features:

• 8-channel NPN Darlington transistor array

• Up to 500mA per channel

• Supports load voltages up to 50V

• Built-in flyback diodes for inductive loads

• TTL/CMOS compatible inputs

• Ideal for relays, motors, LEDs, solenoids, and displays

• Direct companion to shift registers like 74HC595