ULN2003 consists of high voltage resistant and large current Darlington transistors, with seven Darlington-NPN transistors; Each pair of ULN2003 with 2.7K base resistance in series connection and can directly connect with TTL / CMOS circuit under 5V working voltage; Sinking current: 500mA; Adopts DIP-16 or SOP-16 plastic package; Tamb: 25'C.