ChipScout

Power

ULN2003

Darlington transistor array often sold with 28BYJ-48 stepper motor kits.

China-madeTexas InstrumentsActiveModerate

Best For

Projects needing Driver array and Stepper kit with a commonly available power part.

Avoid If

You need production-grade certainty without checking the exact module vendor, pinout, and library maintenance status.

Quick Decision Notes

ULN2003 is indexed as a power part from Texas Instruments. ChipScout tracks it by practical maker-facing dimensions: interfaces, library readiness, estimated price, field-level sources, and whether the page is strong enough for selection rather than only lookup.

Technical Specifications

FunctionDarlington driverSource: Texas Instruments
Channels7Source: Texas Instruments
UseRelay / stepperSource: Texas Instruments
Working Voltage5V logicSource: Texas Instruments

Common Use Cases

  • Maker prototypes
  • Low-cost modules
  • Educational hardware

Known Issues

  • Breakout boards may use different pin labels or regulator choices
  • Clone modules can differ from the original datasheet part

Interfaces and Library Support

Interfaces
GPIO
Wireless
None
Voltage
3.3V
Libraries
Arduino verifiedMicroPython pending
Data Integrity82% confidence
Sourcehttps://www.ti.com/
Last verified2026-05-20
Core specsVerified
PinoutAvailable
Library supportChecked
Price rangePresent
Found a wrong spec?

Every field is meant to be source-backed. Corrections should include a datasheet URL, vendor page, module photo, or reproducible library test.

Submit correction

Source Resources

Datasheethttps://www.ti.com/Texas InstrumentsLibraryULN2003 Arduino library lookupArduino

Pinout Table

VCC3.3VPower the module from a rail that matches the breakout board, not just the bare IC.
GNDCommon groundConnect ground between the controller, sensor/module, and external power supply.
SignalMCU GPIO / ADCUse a digital input, output, PWM, or ADC pin based on the module output type.

Pinout is not yet source-verified. Use the table as an integration checklist, then confirm exact pins against the module vendor page before wiring hardware.

Common Wiring

VCC

Power the module from a rail that matches the breakout board, not just the bare IC.

GND

Connect ground between the controller, sensor/module, and external power supply.

Signal

Use a digital input, output, PWM, or ADC pin based on the module output type.

Arduino Example

void setup() {
  Serial.begin(115200);
  Serial.println("ULN2003 GPIO wiring smoke test");
}

void loop() {
  // Replace with the maintained ULN2003 library or module protocol.
  Serial.println("Read or toggle the connected signal pin.");
  delay(1000);
}
ULN2003 Arduino library lookup

MicroPython Example

MicroPython support is pending. Treat community scripts as prototypes until a maintained driver is linked and tested on a known development board.

Recommended Development Boards

ESP32-C3 development board

Low-cost Wi-Fi/BLE board with enough interfaces for most sensors and modules.

Arduino Uno R4 / compatible

Good baseline for beginner wiring and library validation.

Raspberry Pi Pico W

Practical MicroPython target for I2C, SPI, UART, PWM, and ADC experiments.

Alternative Model Reasons

18650 Battery HolderPowerCompare this option when price or module availability is the deciding constraint.
74HC595PowerChoose this when MicroPython support is required for fast prototyping.
A4988PowerThis alternative currently has stronger source coverage and confidence in ChipScout.
AMS1117-3.3PowerCompare this option when price or module availability is the deciding constraint.

Common Questions

What is ULN2003 best used for?

Projects needing Driver array and Stepper kit with a commonly available power part.

Does ULN2003 support Arduino or MicroPython?

ULN2003 has verified Arduino support and MicroPython support pending verification.

What interfaces does ULN2003 use?

ULN2003 lists GPIO; wireless support is no wireless protocol.

Compare ULN2003 vs 18650 Battery Holder

Alternatives and Related Parts

18650 Battery Holder

Generic

Battery holder component useful to include because many maker power designs depend on its mechanical format.

China-madePower64% confidence

74HC595

Nexperia

8-bit shift register used to expand outputs for LEDs, relays, and simple digital control.

China-madePower86% confidence

A4988

Allegro MicroSystems

Common stepper motor driver used in older 3D printer and CNC control boards.

China-madePower86% confidence

AMS1117-3.3

Advanced Monolithic Systems

Legacy linear regulator used on many Arduino and ESP breakout boards.

China-madePower76% confidence