72. NPN Transistor for Relay Coil Driver

Aarav is designing an embedded control board where a 3.3V MCU GPIO needs to switch a 12V relay coil.

The relay coil draws about 70mA.

Since the GPIO cannot drive the relay directly, he wants to use an NPN transistor as a low-side switch.

The transistor base will be driven from the 3.3V GPIO through a series resistor.

He wants an SOT-23 SMD package for compact layout.

Help him select a suitable NPN transistor from DigiKey.

Make sure it can handle the relay coil current with a margin, has low saturation voltage, and works reliably in industrial temperatures.