The ULN2003A is a Darlington transistor array chip. It is ideal for unipolar stepper motors such as the 28BYJ-48 and many others. On the inputs, you can connect them directly to a microcontroller or an arduino. The output connector can connect directly to the 28BYJ-48. Since the darlington transistor network requires only 4 pins for a 5-pin stepper, you can use the other remaining transistors in the network to drive inductive loads. The card contains a network of ULN2003A darlington transistors, a decoupling capacitor, 4 LEDs and their current limiting resistors. A connector for a stepper motor and header pins for inputs and power. How to use Connect the inputs to a microcontroller or an arduino, connect a power source and a unipolar stepper motor to the outputs. The LEDs will light up for each sequence.
