ULN2003 is 7x NPN Transistor Array with built in base resistor and diode for inductive loads, Example - Drive 12V relays & stepper motors from 3-5V MCU signal.
The ULN2003A is an array of seven NPN Darlington transistors capable of 500mA, 50V output. It features common-cathode flyback diodes for switching inductive loads.
Typical Applications