ULN2003 Darlington Array (DIP / board)
by TI / ST
SKU: PSA-CMP-ULN2003
No reviews yetTypical India street price
₹15–₹60
Drive relays, unipolar steppers, lamps from MCU pins.
Interface: 7 open-collector outputs
Always drive through an H-bridge (L298N/TB6612), never from a GPIO pin.
Connect motor terminals to driver OUT; driver IN/PWM to MCU.
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Concept
Seven Darlington transistors with built-in flyback diodes, one GND.
A little theory
Sinking driver: pin HIGH → output LOW → load on +V turns on. ~500 mA/ch not all at once. In the classroom, treat ULN2003 Darlington Array (DIP / board) as a beginner part using 7 open-collector outputs. Typical India street price is about ₹15–₹60. Always verify voltage and pin labels on your exact module — silk screens vary across clones. Start with a datasheet or trusted learn guide, power the part correctly, share GND with the MCU, and test with a simple blink/read sketch before building the full project. Measure voltages with a multimeter when something fails, and keep actuator current off the MCU regulator.
How it works in a project
Stepper board: IN1–IN4 from MCU, 5 V to stepper center taps.
Classroom & project use
- 28BYJ-48 stepper
- Relay banks
- LED bars
Buying in India
Precautions
- Check 3.3 V MCU compatibility before connecting signal pins
- Share a common GND with the microcontroller
Specifications
| Channels | 7 |
| Type | Darlington sink |
| Category | Drivers & Relays |
| Difficulty | Beginner |
| Voltage | 5V logic; outputs to 50 V |
| Interface | 7 open-collector outputs |
Pinout
See module silkscreen: typically VCC, GND, and signal pins. Confirm labels against the seller photo — clones vary.
